Rupinder Tewari

Panjab University, Chandigarh, Chandīgarh, India

Are you Rupinder Tewari?

Claim your profile

Publications (49)113.96 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A nitrile-hydrolysing bacterium, identified as Isoptericola variabilis RGT01, was isolated from industrial effluent through enrichment culture technique using acrylonitrile as the carbon source. Whole cells of this microorganism exhibited a broad range of nitrile-hydrolysing activity as they hydrolysed five aliphatic nitriles (acetonitrile, acrylonitrile, propionitrile, butyronitrile and valeronitrile), two aromatic nitriles (benzonitrile and m-Tolunitrile) and two arylacetonitriles (4-Methoxyphenyl acetonitrile and phenoxyacetonitrile). The nitrile-hydrolysing activity was inducible in nature and acetonitrile proved to be the most efficient inducer. Minimal salt medium supplemented with 50 mM acetonitrile, an incubation temperature of 30 °C with 2 % v/v inoculum, at 200 rpm and incubation of 48 h were found to be the optimal conditions for maximum production (2.64 ± 0.12 U/mg) of nitrile-hydrolysing activity. This activity was stable at 30 °C as it retained around 86 % activity after 4 h at this temperature, but was thermolabile with a half-life of 120 min and 45 min at 40 °C and 50 °C respectively.
    Indian Journal of Microbiology 06/2014; 54(2). · 0.46 Impact Factor
  • The Journal of infection 01/2014; · 4.13 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Optimization of cultural conditions for enhanced cellulase production by Aspergillus niger NS-2 were studied under solid-state fermentation. Significant increase in yields (CMCase 463.9 ± 20.1 U/g, FPase 101.1 ± 3.5 U/g and β-glucosidase 99 ± 4.0 U/g) were obtained under optimized conditions. Effect of different nutritional parameters was studied to induce the maximum production of cellulase complex. Scale-up studies for enzyme production process were carried out. Characterization studies showed that enzymes produced by A. niger NS-2 were highly temperature- and pH stable. At 50 °C, the half life for CMCase, FPase, β-glucosidase were approximately 240 h. Cellulases from A. niger NS-2 were stable at 35 °C for 24 h over a broader pH range of 3.0-9.0. We examined the feasibility of using steam pretreatment to increase the saccharification yields from various lignocellulosic residues for sugar release which can potentially be used in bioethanol production. Saccharification of pretreated dry potato peels, carrot peels, composite waste mixture, orange peels, onion peels, banana peels, pineapple peels by crude enzyme extract from A. niger NS-2, resulted in very high cellulose conversion efficiencies of 92-98 %.
    Applied biochemistry and biotechnology 09/2013; · 1.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The emergence of multi-drug-resistant bacterial pathogens along with labor-intensive and time-consuming drug discovery methods has put an emphasis on alternative approaches which can overcome these drawbacks. One such approach is in silico identification of novel bacterial inhibitors using structure-based drug design methodology. In the present study, novel inhibitors have been proposed against two essential enzymes (MurA and MurZ) involved in the biosynthesis of cell wall of Enterococcus faecalis, a serious nosocomial bacterial pathogen. Homology models of MurA and MurZ of E. faecalis were constructed using template MurA of Enterobacter cloacae and Haemophilus influenza, respectively. The validation of the refined models, using Ramachandran, Errat and ProSA energy plots, showed that constructed models were reliable and of good quality. The active site amino acid residues, as predicted by CASTp server, were in accordance with the residues identified from MurA crystal structures available for other bacteria. The present study revealed for the first time the importance of two additional amino acid residues (Thr305 and Tyr329) in MurA and MurZ enzymes, which might be crucial for the binding of ligands/inhibitors with the target. Based on the GLIDE score and interaction profile, 5-sulfonoxyanthranilic acid derivatives, T6361 and T6362 were found to be the potential inhibitors of MurA and MurZ enzymes.
    Medicinal Chemistry Research 09/2013; · 1.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Emergence of the multidrug-resistant pathogens has rendered the current therapies ineffective thereby, resulting in the need for new drugs and drug targets. The accumulating protein sequence data has initiated a drift from classical drug discovery protocols to structure-based drug designing. In the present study, in silico subtractive genomics approach was implemented to find a set of potential drug targets present in an opportunist bacterial pathogen, Acinetobacter baumannii (A. baumannii). Out of the 43 targets identified, further studies for protein model building and lead-inhibitor identification were carried out on two cell-essential targets, MurA and MurB enzymes (of A. baumannii designated as MurAAb and MurBAb) involved in the peptidoglycan biosynthesis pathway of bacteria. The homology model built for each of them was further refined and validated using various available programs like PROCHECK, Errat, ProSA energy plots, etc. Compounds showing activity against MurA and MurB enzymes of other organisms were collected from the literature and were docked into the active site of MurAAb and MurBAb enzymes. Three inhibitors namely, T6361, carbidopa, and aesculin, showed maximum Glide score, hydrogen bonding interactions with the key amino acid residues of both the enzymes and acceptable ADME properties. Furthermore, molecular dynamics simulation studies on MurAAb-T6361 and MurBAb-T6361 complexes suggested that the ligand has a high binding affinity with both the enzymes and the hydrogen bonding with the key residues were stable in the dynamic condition also. Therefore, these ligands have been propsed as dual inhibitors and promising lead compounds for the drug design against MurAAb and MurBAb enzymes.
    Applied biochemistry and biotechnology 07/2013; · 1.94 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Loop-mediated isothermal amplification (LAMP) assay has come forward as a rapid, cost-effective molecular technique for diagnosis of tuberculosis (TB) in developing countries. This study evaluated Mycobacterium tuberculosis-specific in-house LAMP assay targeting 16s rRNA and compared it with other conventional tests and nucleic acid amplification assay (IS6110 PCR). A total of 133 sputum specimens (103 from suspected pulmonary TB cases and 30 from non-TB controls) were subjected to conventional tests, IS6110 PCR and 16s rRNA LAMP assay. Of the 103 patients, the maximum number of cases were found to be positive by LAMP assay, that is, in 87 (84.5%) patients, followed by culture positive in 78 (75.7%), IS6110 PCR in 74 (71.8%), and smear positive in 70 (67.9%) patients. Of the 83 smear positive and/or culture positive cases, LAMP detected 77 (92.77%) cases, and was found to be superior to IS6110 PCR, which could detect 69 (83.1%) cases; a concordance of 0.6 was obtained between the two tests using kappa statistics. Overall, LAMP was simple and efficacious for early diagnosis of smear positive, culture positive cases as well as for confirmation of smear negative, culture negative cases, and was found to be superior to IS6110 PCR.
    Journal of Clinical Laboratory Analysis 07/2013; 27(4):272-6. · 1.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Mycobacterium tuberculosis (M.tb) is the causative agent of tuberculosis, killing ~1.7 million people annually. The remarkable capacity of this pathogen to escape the host immune system for decades and then to cause active tuberculosis disease, makes M.tb a successful pathogen. Currently available anti-mycobacterial therapy has poor compliance due to requirement of prolonged treatment resulting in accelerated emergence of drug resistant strains. Hence, there is an urgent need to identify new chemical entities with novel mechanism of action and potent activity against the drug resistant strains. RESULTS: This study describes novel computational models developed for predicting inhibitors against both replicative and non-replicative phase of drug-tolerant M.tb under carbon starvation stage. These models were trained on highly diverse dataset of 2135 compounds using four classes of binary fingerprint namely PubChem, MACCS, EState, SubStructure. We achieved the best performance Matthews correlation coefficient (MCC) of 0.45 using the model based on MACCS fingerprints for replicative phase inhibitor dataset. In case of non-replicative phase, Hybrid model based on PubChem, MACCS, EState, SubStructure fingerprints performed better with maximum MCC value of 0.28. In this study, we have shown that molecular weight, polar surface area and rotatable bond count of inhibitors (replicating and non-replicating phase) are significantly different from non-inhibitors. The fragment analysis suggests that substructures like hetero_N_nonbasic, heterocyclic, carboxylic_ester, and hetero_N_basic_no_H are predominant in replicating phase inhibitors while hetero_O, ketone, secondary_mixed_amine are preferred in the non-replicative phase inhibitors. It was observed that nitro, alkyne, and enamine are important for the molecules inhibiting bacilli residing in both the phases. In this study, we introduced a new algorithm based on Matthews correlation coefficient called MCCA for feature selection and found that this algorithm is better or comparable to frequency based approach. CONCLUSION: In this study, we have developed computational models to predict phase specific inhibitors against drug resistant strains of M.tb grown under carbon starvation. Based on simple molecular properties, we have derived some rules, which would be useful in robust identification of tuberculosis inhibitors. Based on these observations, we have developed a webserver for predicting inhibitors against drug tolerant M.tb H37Rv available at http://crdd.osdd.net/oscadd/mdri/.
    Chemistry Central Journal 03/2013; 7(1):49. · 1.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aims: In view of the changing sensitivity pattern of Salmonella, this study was carried out to investigate the current antibiogram and clonal relatedness among the drug-resistant Salmonella enterica serovar Typhi in Northern India. Results: Re-emergence in the sensitivity to chloramphenicol and cotrimoxazole with increase in the resistance to various quinolones has been observed. The efficacy of nalidixic acid resistance to be used as a marker for decrease in sensitivity to ciprofloxacin may vary. Clonal differences on the basis of amplification of repetitive elements (rep-PCR) were found in the two different areas within the same region. Conclusions: The present study creates a paramount baseline for rationalizing the judicious use of quinolones and re-examine the use of chloramphenicol and cotrimoxazole. Molecular analysis of clinical Salmonella isolates depicts the clonal expansion of the isolates that may serve as a reference to which newer outbreak strains can be compared. rep-PCR techniques may be useful in molecular discrimination of isolates for better understanding of the Salmonella epidemiology and as a basis for development of rational control strategies.
    Microbial drug resistance (Larchmont, N.Y.) 01/2013; · 1.99 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Like any other enteric pathogen, Salmonella also encounters acidic stress in the stomach as well as within the host macrophage milieu. However, the pathogen is reported to combat this stress through acid tolerance response (ATR), expressing a number of genes and eventually the proteins. Recently, an acid induced outer membrane phenotype encoded by fliC gene in Salmonella enterica serovar Typhi has been identified. In the present study, fliC gene was cloned to study its biological implications. The recombinant FliC (rFliC) protein was observed to stimulate the production of antibodies. These antibodies could also recognize the FliC protein (antigen) in the clinical samples i.e. blood samples from typhoid patents as well as healthy blood samples spiked with serovar Typhi. Moreover, the rFliC also reacted with the sera from patients suffering with typhoid fever indicating its in-vivo immunogenicity. Ex-vivo study revealed that rFliC has the potential to stimulate the macrophages to generate higher levels of inflammatory mediators such as malondialdehyde (MDA) and nitrite. The inflammatory potential of FliC was also confirmed in-vivo, by the paw oedema test as well as by flicking response of the inflamed paw indicating hyperalgesia occurring during inflammatory response. The findings of the present study indicate that acid induced FliC might be one of the factors enhancing the virulence of serovar Typhi under the host acidic conditions and may prove to be helpful in designing the prophylactic measures.
    AMB Express. 10/2012; 2(1):55.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Restriction fragment length polymorphism (RFLP) based on IS6110 is considered the gold standard for Mycobacterium tuberculosis molecular typing. It is useful to discriminate among M. tuberculosis strains, investigate outbreaks and distinguish between reactivation and re-infection. We studied polymorphisms among M. tuberculosis isolates from northern India using RFLP to determine the presence of a correlation between IS6110 based fingerprints and drug resistance and to look for relapse and transmission among patients and their contacts. RFLP patterns of PvuII digested genomic DNA of 100 M. tuberculosis isolates were analyzed using southern blotting with a 245 bp IS6110 probe. Drug sensitivity testing (DST) was conducted for rifampicin (40 microg/ml), isoniazid (1 microg/ml), ethambutol (2 microg/ml) and streptomycin (4 microg/ml) using the proportion method. A high degree of polymorphism was seen among the M. tuberculosis isolates and the number of IS6110 copies varied from 0 to 14, with a predominance of isolates with 11 bands. Seventy-five isolates had a high number of bands, 9 had an intermediate number, 6 isolates had a low number and 10 isolates had no bands. No correlation between IS6110 band numbers and RFLP banding patterns was found with drug resistance or for any particular geographical area, although clustering was seen amongst MDR-TB cases. No cases of relapses or transmissions were seen.
    The Southeast Asian journal of tropical medicine and public health 09/2012; 43(5):1161-8. · 0.61 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Background: The diagnosis of pulmonary tuberculosis is still a major challenge. Using a polymerase chain reaction (PCR), one can detect Mycobacterium tuberculosis in clinical samples within a few hours. However, single gene targets may result in false negativity due to the absence of target DNA in some M. tuberculosis isolates. The objective of this study was to develop and evaluate a multiplex PCR (M-PCR) using IS6110 and devR primers for the detection of M. tuberculosis in sputum samples. Methods: Sputum samples were collected from: (1) 200 confirmed cases of tuberculosis; (2) 100 suspected cases of tuberculosis diagnosed on the basis of clinical and radiological findings; (3) 200 non-tubercular patients suffering from respiratory diseases other than tuberculosis, in whom tuberculosis had been excluded. All 500 sputum samples were subjected to PCR using IS6110 primers, and M-PCR using IS6110 and devR primers; results were compared with conventional techniques. Results: It was found that M-PCR was 97.5% successful in detecting the presence of tuberculosis in the confirmed tuberculosis group as compared to 84.5% by IS6110-based PCR. In the suspected tuberculosis group, M-PCR could detect 45% of cases as compared to 40% by IS6110-based PCR. Overall, the specificities of both the PCR and M-PCR were found to be 96.5%. Conclusions: This study demonstrated that the M-PCR assay is more sensitive than the IS6110-based PCR for the detection of M. tuberculosis in sputum specimens and could be applied in situations of highly suspected tuberculosis when all others tests including IS6110 PCR are negative.
    Scandinavian Journal of Infectious Diseases 06/2012; 44(10):739-44. · 1.71 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aspartate-semialdehyde dehydrogenase (Asd; ASADH; EC 1.2.1.11) is the enzyme that lies at the first branch point in the biosynthetic pathway of important amino acids including lysine and methionine and the cell-wall component diaminopimelate (DAP). The enzymatic reaction of ASADH is the reductive dephosphorylation of aspartyl-β-phosphate (ABP) to aspartate β-semialdehyde (ASA). Since the aspartate pathway is absolutely essential for the survival of many microbes and is absent in humans, the enzymes involved in this pathway can be considered to be potential antibacterial drug targets. In this work, the structure of ASADH from Mycobacterium tuberculosis H37Rv (Mtb-ASADH) has been determined in complex with glycerol and sulfate at 2.18 Å resolution and in complex with S-methyl-L-cysteine sulfoxide (SMCS) and sulfate at 1.95 Å resolution. The overall structure of Mtb-ASADH is similar to those of its orthologues. However, in the Mtb-ASADH-glycerol complex structure the glycerol molecule is noncovalently bound to the active-site residue Cys130, while in the Mtb-ASADH-SMCS complex structure the SMCS (Cys) is covalently linked to Cys130. The Mtb-ASADH-SMCS complex structurally mimics one of the intermediate steps in the proposed mechanism of ASADH enzyme catalysis. Comparison of the two complex structures revealed that the amino acids Glu224 and Arg249 undergo conformational changes upon binding of glycerol. Moreover, the structures reported here may help in the development of species-specific antibacterial drug molecules against human pathogens.
    Acta Crystallographica Section D Biological Crystallography 06/2012; 68(Pt 6):671-9. · 12.67 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Various agricultural and kitchen waste residues were assessed for their ability to support the production of a complete cellulase system by Aspergillus niger NS-2 in solid state fermentation. Untreated as well as acid and base-pretreated substrates including corn cobs, carrot peelings, composite, grass, leaves, orange peelings, pineapple peelings, potato peelings, rice husk, sugarcane bagasse, saw dust, wheat bran, wheat straw, simply moistened with water, were found to be well suited for the organism's growth, producing good amounts of cellulases after 96 h without the supplementation of additional nutritional sources. Yields of cellulases were higher in alkali treated substrates as compared to acid treated and untreated substrates except in wheat bran. Of all the substrates tested, wheat bran appeared to be the best suited substrate producing appreciable yields of CMCase, FPase and β-glucosidase at the levels of 310, 17 and 33 U/g dry substrate respectively. An evaluation of various environmental parameters demonstrated that appreciable levels of cellulases could be produced over a wide range of temperatures (20-50 °C) and pH levels (3.0-8.0) with a 1:1.5 to 1:1.75 substrate to moisture ratio.
    Waste Management 04/2012; 32(7):1341-6. · 3.16 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of four phosphate solubilizing bacteria (PSB) was studied on growth and aloin-A content of Aloe barbadensis in soil containing tricalcium phosphate (TCP). PSB were identified based on 16S rRNA gene sequencing as Pseudomonas synxantha, Burkholderia gladioli, Enterobacter hormaechei and Serratia marcescens. These PSB solubilized 25-340 μg ml(-1) of TCP into the liquid phase. The treatment of plants with individual PSB or mixture of these increased soil available P, P uptake in plants and plant growth. The increase in aloin-A content due to higher plant biomass and unit biomass production was 673%, 294%, 276%, 119% and 108% in plants treated with a PSB consortium, P. synxantha, S. marcescens, B. gladioli, and E. hormaechei in TCP amended soil, respectively.
    Microbiological Research 03/2012; 167(6):358-63. · 1.99 Impact Factor
  • Acta Crystallographica Section D Biological Crystallography 02/2012; · 14.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Phosphorous (P) is an essential macronutrient required by the plants for their vital functions such as photosynthesis, proteins and nucleic acid production, nitrogen fixation, formation of oil, sugars, starches etc. It is also the part of all biogeochemical cycles in plants. It is least mobile element which is available to plants as phosphate anion. P in precipitated form i.e. Orthophosphate (H 2 PO 4 -1 or HPO 4 2-), is absorbed by Fe 3+ , Ca 2+ or Al 3+ oxides in soil through legend exchange. A large amount of P applied as a fertilizer becomes immobile through precipitation reaction with highly reactive and Fe 3+ in the acidic, and + in calcareous or normal soils. The use of phosphate solubilizing bacteria (PSB) as inoculants in soil increases the phosphorous uptake by the plants and also the crop yield. The ability of phosphate solubilizing bacteria to convert insoluble form of phosphorous into soluble one is an important trait in sustainable farming for increasing crops yield. PSB play an important role in enhancing phosphorous availability to plants by lowering soil pH and by microbial production of organic acids and mineralization of organic P by acid phosphatases. These organisms besides providing P also facilitate the growth of plants by improving the uptake of nutrients and stimulating the production of some phytohormones. PSB have high potential as bio-fertilizers especially in P-deficient soils to enhance the growth and yield performance of crops. The present article describes the progress of research on this area and future insights about use of PSB in agriculture.
    12/2011; 2:2141-5463.
  • Ankur Gautam, Praveen Rishi, Rupinder Tewari
    [Show abstract] [Hide abstract]
    ABSTRACT: The emergence of antibiotic resistance in bacterial pathogens has foxed the health organizations which are actively scrambling for solutions. The available data indicate an increased morbidity in infections often leading to mortality among patients where drug-resistant pathogens have negated the effect of the medicines. In the context of developing "novel bacterial inhibitors" for killing or arresting the growth of drug-resistant pathogens, UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) is an enzyme that provides hope for the future. This enzyme catalyzes the first committed step in the biosynthesis of peptidoglycan, an integral and essential component of the bacterial cell wall. MurA enzyme is neither present nor required by mammals and shows poor homology with human proteins. Therefore, it is an ideal target for antibacterial chemotherapy. Till date, 18 structures of MurA (in native and ligand-bound forms) from different bacterial pathogens have been solved. In the last 2 years, eight structures of bacterial MurA have been submitted to the Protein Data Bank and many inhibitors discovered. The present review discusses the structural and functional features of MurA of bacterial pathogens along with the development of MurA-targeted inhibitors.
    Applied Microbiology and Biotechnology 08/2011; 92(2):211-25. · 3.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Biofertilizers offer alternative means to pro-moting cultivation of medicinal plants less dependent on chemical fertilizers. Present study was aimed at evaluating the potential of phosphate-solubilizing bacteria (PSB) Burkholderia gladioli MTCC 10216, B. gladioli MTCC 10217, Enterobacter aerogenes MTCC 10208 and Serratia marcescens MTCC 10238 for utilizing Mussoorie rock phosphate (MRP) to enhance plant growth, and stevioside (ST) and rebaudioside-A (R-A) contents of Stevia rebau-diana. The solubilization of MRP by PSB strains varied from 1.4 to 15.2 lg ml -1 , with the highest solubilization by Enterobacter aerogenes 10208. The PSB treatment increased the growth and ST and R-A contents of plants. Plant growth and stevioside contents were more pro-nounced with plants treated with a mixture of strains and grown in MRP amended soil compared to the unamended soil. The increment in shoot length (47.8%), root length (17.4%), leaf dry weight (164%), stem dry weight (116%), total shoot biomass (136%) resulted in enhanced produc-tivity of ST (291%) and R-A (575%) in plants inoculated with mixture of PSB as compared to the uninoculated plants. The soils of PSB treated plants contained more available P than the soils of uninoculated plants (increase of 86–576%). PSB inoculated plants also recorded higher P content (64–273% increase) compared to uninoculated plants. The PSB strains differed in the extent of rhizosphere colonization, carbon source utilization pattern and whole cell fatty acids methyl esters composition.
    Plant Growth Regulation 08/2011; 65(3-ISSN: 0167-6903 (Print) 1573-5087 (Online)):449-457. · 1.67 Impact Factor
  • Source
    Sanjeev Kumar, Rohit Sharma, Rupinder Tewari
    [Show abstract] [Hide abstract]
    ABSTRACT: The pharmaceutically important compound N-acetylglucosamine (NAG), is used in various therapeutic formulations, skin care products and dietary supplements. Currently, NAG is being produced by an environment-unfriendly chemical process using chitin, a polysaccharide present in abundance in the exoskeleton of crustaceans, as a substrate. In the present study, we report the potential of an eco-friendly biological process for the production of NAG using recombinant bacterial enzymes, chitinase (CHI) and chitobiase (CHB). The treatment of chitin with recombinant CHI alone produced 8% NAG and 72% chitobiose, a homodimer of NAG. However, supplementation of the reaction mixture with another recombinant enzyme, CHB, resulted in approximately six fold increase in NAG production. The product, NAG, was confirmed by HPLC, TLC and ESI-MS studies. Conditions are being optimized for increased production of NAG from chitin.
    Indian Journal of Microbiology 07/2011; 51(3):319-25. · 0.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The intracellular enzyme dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52) from Pseudomonas aeruginosa is a potential drug target because it is essential for the growth of bacteria while it is absent in humans. Therefore, in order to design new compounds using structure based approach for inhibiting the function of DHDPS from P. aeruginosa (Ps), we have cloned, characterized biochemically and biophysically and have determined its three-dimensional structure. The gene encoding DHDPS (dapA) was cloned in a vector pET-28c(+) and the recombinant protein was overexpressed in the Escherichia coli host. The K(m) values of the recombinant enzyme estimated for the substrates, pyruvate and (S)-aspartate-β-semialdehyde [(S)-ASA] were found to be 0.90±0.13 mM and 0.17±0.02 mM, respectively. The circular dichroism studies showed that the enzyme adopts a characteristic β/α conformation which is retained up to 65°C. The fluorescence data indicated the presence of exposed tryptophan residues in the enzyme. The three-dimensional structure determination showed that DHDPS forms a homodimer which is stabilized by several hydrogen bonds and van der Waals forces at the interface. The active site formed with residues Thr44, Tyr107 and Tyr133 is found to be stereochemically suitable for catalytic function. It may be noted that Tyr107 of the catalytic triad belongs to the partner molecule in the dimer. The structure of the complex of PsDHDPS with (S)-lysine determined at 2.65 Å resolution revealed the positions of three lysine molecules bound to the protein.
    International journal of biological macromolecules 03/2011; 48(5):779-87. · 2.37 Impact Factor

Publication Stats

673 Citations
113.96 Total Impact Points

Institutions

  • 2000–2014
    • Panjab University
      • • Centre for Microbial Biotechnology
      • • Department of Biotechnology
      • • Department of Microbiology
      Chandigarh, Chandīgarh, India
  • 2012
    • Postgraduate Institute of Medical Education and Research
      • Department of Medical Microbiology
      Chandīgarh, Union Territory of Chandigarh, India
  • 2010–2011
    • Bioinformatics Institute of India
      Noida, Uttar Pradesh, India
    • Institute of Microbial Technology
      • Bioinformatics Centre (IMTECH)
      Chandīgarh, Union Territory of Chandigarh, India
  • 2006
    • National Institute of Immunology
      New Dilli, NCT, India
  • 2001
    • Central University of Punjab
      BUP, Punjab, India