Publications (5)16.7 Total impact
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Article: New lead structures in antifungal drug discovery.
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ABSTRACT: During the past two decades, the incidence of invasive fungal infections has been increasing dramatically. Clinical available antifungal agents have several drawbacks such as limited potency and spectrum, drug related toxicity, non-optimal pharmacokinetics, and severe resistance. There is an emergent need to develop new antifungal drugs with novel chemical structures and novel mechanism of action. This review will focus on the most significant achievements in the discovery of antifungal lead structures within last few years. In particular, we pay more attention on the structure-activity relationship of antifungal leads and provide perspectives for future antifungal drug discovery.Current Medicinal Chemistry 01/2011; 18(5):733-66. · 4.86 Impact Factor -
Article: Homology modeling of lanosterol 14alpha-demethylase of Candida albicans and Aspergillus fumigatus and insights into the enzyme-substrate Interactions.
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ABSTRACT: The crystal structure of 14alpha-sterol demethylase from Mycobacterium tuberculosis (MT_14DM) provides a good template for modeling the three dimensional structure of lanosterol 14alpha-demethylase, which is the target of azole antifungal agents. Homologous 3D models of lanosterol 14alpha-demethylase from Candida albicans (CA_14DM) and Aspergillus fumigatus (AF_14DM) were built on the basis of the crystal coordinates of MT_14DM in complex with 4-phenylimidazole and fluconazole. The reliability of the two models was assessed by Ramachandran plots, Profile-3D analysis, and by analyzing the consistency of the two models with the experimental data on the P450(14DM). The overall structures of the resulting CA_14DM model and AF_14DM model are similar to those of the template structures. The two models remain the core structure characteristic for cytochrome P450s and most of the insertions and deletions expose the molecular surface. The structurally and functionally important residues such as the heme binding residues, the residues lining the substrate access channel, and residues in active site were identified from the model. To explore the binding mode of the substrate with the two models, 24(28)-methylene-24,25-dihydrolanosterol was docked into the active site of the two models and hydrophobic interaction and hydrogen-bonding were found to play an important role in substrate recognition and orientation. These results provided a basis for experiments to probe structure-function relationships in the P450(14DM). Although CA_14DM and AF_14DM shared similar core structural character, the active site of the two models were quite different, thus allowing the rational design of specific inhibitors to the target enzyme and the discovery of novel antifungal agents with broad spectrum.Journal of biomolecular structure & dynamics 09/2004; 22(1):91-9. · 4.99 Impact Factor -
Article: A three-dimensional model of lanosterol 14alpha-demethylase of Candida albicans and its interaction with azole antifungals.
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ABSTRACT: The three-dimensional structure of lanosterol 14alpha-demethylase (P450(14DM), CYP51) of Candida albicans was modeled on the basis of crystallographic coordinates of four prokaryotic P450s: P450BM3, P450cam, P450terp, and P450eryF. The P450(14DM) sequence was aligned to those of known proteins using a knowledge-based alignment method. The main chain coordinates of the core regions were transferred directly from the corresponding coordinates of P450BM3. The side chain conformations of the core regions were determined by the conformations of the equivalent residues with the highest homologous scores in four crystal structures. The model was then refined using molecular mechanics and molecular dynamics. The reliability of the resulting model was assessed by Ramachandran plots, Profile-3D, hydropathy plot analysis, and by analyzing the consistency of the model with the experimental data. The structurally and functionally important residues such as the heme binding residues, the residues interacting with redox-partner protein and/or involved in electron transfer, the residues lining substrate access channel, and the substrate binding residues were identified from the model. These residues are candidates for further site-directed mutagenesis and site-specific antipeptide antibody binding experiments. The active analogue approach was employed to search the pharmacophoric conformations for 14 azole antifungals. The resulting bioactive conformations were docked into the active site of lanosterol 14alpha-demethylase of Candida albicans. All 14 azole antifungals are shown to have a similar docking mode in the active site. The halogenated phenyl group of azole inhibitors is deep in the same hydrophobic binding cleft as the 17-alkyl chain of substrate. The pi-pi stacking interaction might exist between halogenated phenyl ring of inhibitors and the aromatic ring of residue Y132. The long side chains of some inhibitors such as itraconazole and ketoconazole surpass the active site and interact with the residues in the substrate access channel. To compare with mammalian enzymes, structurally selective residues of the active site of fungal lanosterol 14alpha-demethylase are distributed in the C terminus of F helix, beta6-1 sheet and beta6-2 sheet.Journal of Medicinal Chemistry 07/2000; 43(13):2493-505. · 5.25 Impact Factor -
Article: A method of active conformation search based on active and inactive analogues and its application to allylamine antimycotics.
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ABSTRACT: A new program ACSBAIA (Active Conformation Search Based on Active and Inactive Analogues) for determination of the active conformations was developed based on the rationales that specific functional groups of active analogues could reach and interact with the active site of target receptor by means of the change of conformations, but that of inactive analogues could not interact with the active site owing to conformational restriction. The program consisted of 4 sub-programs: conformation sampling system, active conformation constraint system, inactive conformation exclusion system, and activity prediction system. Pharmacophoric conformation of allylamine antimycotics was studied by this method. Activities of 2 analogues were predicted and tested. The results suggested that the method was scientific and practical. The application of this method was not restricted by the three-dimensional structural knowledge of target receptor. In the absence of structural information about the receptor, the method was particularly applicable.Science in China Series C Life Sciences 11/1999; 42(5):538-47. · 1.61 Impact Factor -
Article: Purification and characterization of membrane-bound l-sorbose dehydrogenase from Gluconobacter oxydans GO112
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ABSTRACT: The bacterial strain Gluconobacter oxydans GO112 exhibiting enhanced production of 2-keto-l-gulonic acid (2-KLG) from l-sorbose was bred by this laboratory. l-Sorbose dehydrogenase is one of the key enzymes responsible for the production of 2-KLG. In this study, we purified l-sorbose dehydrogenase from GO112 to homogeneity through sequential chromatographical steps: DEAE-Sepharose Fast Flow, Mono Q anion exchange and Superose 12 gel filtration. The purified l-sorbose dehydrogenase was single subunit protein with apparent molecular weight of about 60 kDa by SDS-PAGE and about 116 kDa by gel filtration chromatography, indicating the l-sorbose dehydrogenase may exist as dimeric molecules under physiological conditions. The optimum pH and temperature for the enzyme were pH 6.86 and 40 °C. It showed good stability at pH 6.2 and temperatures below 30 °C. At 40 °C, the l-sorbose dehydrogenase lost its activity by 37% in the first 1.5 min and then inactivated slowly. The Km value for l-sorbose was 36 mM. The activity of the l-sorbose dehydrogenase was greatly stimulated by Ca2+, while Mn2+, Fe2+, Cu2+, EDTA and citric acid inhibited the activity of the l-sorbose dehydrogenase to different degrees.Enzyme and Microbial Technology.
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Institutions
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1999–2011
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Second Military Medical University, Shanghai
Shanghai, Shanghai Shi, China
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