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ABSTRACT: The title compound, C(56)H(83)N(9)O(9)S·3CH(3)OH, is a methanol tris-olvate of the cyclo-linopeptide cyclo(Met(1)-Leu(2)-Ile(3)-Pro(4)-Pro(5)-Phe(6)-Phe(7)-Val(8)-Ile(9)) (henceforth referred to as CLP-B), which was isolated from flaxseed oil. All the amino acid residues are in an l-configuration based on the CORN rule. The cyclic nona-peptide exhibits eight trans peptide bonds and one cis peptide bond observed between the two proline residues. The conformation is stabilized by an α-turn and two consecutive β-turns each containing a N-H⋯O hydrogen bond between the carbonyl group O atom of the first residue and the amide group H atom of the fourth (α-turn) or the third residue (β-turns), repectively. In the crystal, the components of the structure are linked by N-H⋯O and O-H⋯O hydrogen bonds into chains parallel to the a axis.
Acta Crystallographica Section E Structure Reports Online 01/2012; 68(Pt 1):o50-1. · 0.35 Impact Factor
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ABSTRACT: The title compound, C(56)H(83)N(9)O(11)S·2C(4)H(10)O·H(2)O, is a butanol-water solvate of the cyclo-linopeptide cyclo(Metsulfone(1)-Leu(2)-Ile(3)-Pro(4)-Pro(5)-Phe(6)-Phe(7)-Val(8)-Ile(9)) (henceforth referred to as CLP-K) which was isolated from flax oil. All the amino acid residues are in an l configuration based on the CORN rule. The cyclic nona-peptide exhibits eight trans peptide bonds and one cis peptide bond observed between the two proline residues. The conformation is stabilized by an α- and a β-turn, each containing an N-H⋯O hydrogen bond between the carbonyl group O atom of the first residue and the amide group H atom of the fourth (α-turn) and the third residue (β-turn), repectively. In the crystal, the components of the structure are linked by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds into a two-dimensional network parallel to (001). The -C(H(2))OH group of one of the butanol solvent mol-ecules is disordered over two sets of sites with refined occupancies of 0.863 (4) and 0.137 (4).
Acta Crystallographica Section E Structure Reports Online 09/2011; 67(Pt 9):o2360-1. · 0.35 Impact Factor
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ABSTRACT: The relationship between starch physical properties and enzymatic hydrolysis was determined using ten different hulless barley genotypes with variable carbohydrate composition. The ten barley genotypes included one normal starch (CDC McGwire), three increased amylose starches (SH99250, SH99073, and SB94893), and six waxy starches (CDC Alamo, CDC Fibar, CDC Candle, Waxy Betzes, CDC Rattan, and SB94912). Total starch concentration positively influenced thousand grain weight (TGW) (r(2) = 0.70, p < 0.05). Increase in grain protein concentration was not only related to total starch concentration (r(2) = -0.80, p < 0.01) but also affected enzymatic hydrolysis of pure starch (r(2) = -0.67, p < 0.01). However, an increase in amylopectin unit chain length between DP 12-18 (F-II) was detrimental to starch concentration (r(2) = 0.46, p < 0.01). Amylose concentration influenced granule size distribution with increased amylose genotypes showing highly reduced volume percentage of very small C-granules (<5 μm diameter) and significantly increased (r(2) = 0.83, p < 0.01) medium sized B granules (5-15 μm diameter). Amylose affected smaller (F-I) and larger (F-III) amylopectin chains in opposite ways. Increased amylose concentration positively influenced the F-III (DP 19-36) fraction of longer DP amylopectin chains (DP 19-36) which was associated with resistant starch (RS) in meal and pure starch samples. The rate of starch hydrolysis was high in pure starch samples as compared to meal samples. Enzymatic hydrolysis rate both in meal and pure starch samples followed the order waxy > normal > increased amylose. Rapidly digestible starch (RDS) increased with a decrease in amylose concentration. Atomic force microscopy (AFM) analysis revealed a higher polydispersity index of amylose in CDC McGwire and increased amylose genotypes which could contribute to their reduced enzymatic hydrolysis, compared to waxy starch genotypes. Increased β-glucan and dietary fiber concentration also reduced the enzymatic hydrolysis of meal samples. An average linkage cluster analysis dendrogram revealed that variation in amylose concentration significantly (p < 0.01) influenced resistant starch concentration in meal and pure starch samples. RS is also associated with B-type granules (5-15 μm) and the amylopectin F-III (19-36 DP) fraction. In conclusion, the results suggest that barley genotype SH99250 with less decrease in grain weight in comparison to that of other increased amylose genotypes (SH99073 and SH94893) could be a promising genotype to develop cultivars with increased amylose grain starch without compromising grain weight and yield.
Journal of Agricultural and Food Chemistry 04/2011; 59(9):4743-54. · 2.82 Impact Factor
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ABSTRACT: The asymmetric unit of the title compound, [K(C(3)H(7)O(3))](n) or K[H(2)gl](n), common name potassium glycerolate, contains half the K(+) cation and half of the glycerolate anion. The other half of the anion is generated through a mirror plane passing through the K atom, and a C, an H and an O atom of the glycerolate ligand. The K(+) ion is coordinated by the O atoms of the OH groups, leading to a six-membered chelate ring that adopts a very distorted boat conformation. The negatively charged O atom of the glycerolate anion, [H(2)gl(-)], is found in the flagpole position and forms an ionic bond with the K(+) ion. The O atoms of the hydroxo groups are coordinated to two K(+) ions, whereas the negatively charged O atom is bonded to one K(+) ion. The K(+) ion is coordinated by three other symmetry-related monodentate H(2)gl(-) ligands, so that each H(2)gl(-) ligand is bonded to two K(+) ions, and the potassium has a seven-coordinate environment. The H(2)gl(-) ligands are connected via a strong O-H⋯O hydrogen bond and, together with the K⋯O inter-connections, form polymeric sheets which propagate in the directions of the a and b axes.
Acta Crystallographica Section E Structure Reports Online 01/2011; 67(Pt 2):m141-2. · 0.35 Impact Factor
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ABSTRACT: Human tumor suppressor gene RIZ encodes two protein products, tumor suppressor RIZ1 and proto-oncoprotein RIZ2, which regulate cellular functions in a Yin-Yang fashion. The only structural difference between them is that RIZ2 lacks the N-terminal PR domain. In this study, we showed that RIZ1 mRNA expression level was elevated in stage IV of eight different types of cancer (stage III for prostate cancer), indicating that RIZ1 might play an important role in tumor metastasis, and the PR domain alone possessed anticancer activity.
International journal of medical sciences 01/2011; 8(2):161-7. · 2.24 Impact Factor
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ABSTRACT: Dichlorohydroquinone dioxygenase (PcpA) is the ring-cleavage enzyme in the PCP biodegradation pathway in Sphingobium chlorophenolicum strain ATCC 39723. PcpA dehalogenates and oxidizes 2,6-dichlorohydroquinone to form 2-chloromaleylacetate, which is subsequently converted to succinyl coenzyme A and acetyl coenzyme A via 3-oxoadipate. Previous studies have shown that PcpA is highly substrate-specific and only uses 2,6-dichlorohydroquinone as its substrate. In the current study, we overexpressed and purified recombinant PcpA and showed that PcpA was highly alkaline resistant and thermally stable. PcpA exhibited two activity peaks at pH 7.0 and 10.0, respectively. The apparent k(cat) and K(m) were measured as 0.19 ± 0.01 s(-1) and 0.24 ± 0.08 mM, respectively at pH 7.0, and 0.17 ± 0.01 s(-1) and 0.77 ± 0.29 mM, respectively at pH 10.0. Electron paramagnetic resonance studies showed rapid oxidation of Fe(II) to Fe(III) in PcpA and the formation of a stable radical intermediate during the enzyme catalysis. The stable radical was predicted to be an epoxide type dichloro radical with the unpaired electron density localized on C3.
International journal of biological sciences 01/2011; 7(8):1171-9. · 2.70 Impact Factor
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ABSTRACT: Starch samples extracted from barley cultivars with varying AM concentrations were imaged by AFM using intermittent contact mode. Two different deposition methods were used: a simple solution drop and an aerosol spray deposition. Using the drop deposition method, starch appeared mainly as small particles and aggregated globules, with average heights of 1.8 ± 0.2, 2.7 ± 0.7, and 5.5 ± 1.0 nm, for starch solutions containing increased (38%), normal (25.8%), and undetectable (0%) AM, respectively. The aerosol spray deposition method allowed analysis of individual biopolymer chains of AM and biopolymer fibrils of AP. The image of normal starch showed individual AM chains with an average height of 0.8 ± 0.2 nm, and an average contour length of 178 ± 127 nm. For increased AM starch, the height of individual AM chains was similar to normal starch, but the average contour length was shorter (140 ± 70 nm). All barley starches showed fibril bundles of AP with average heights of 1.9 to 2.9 nm and lengths in the micron size range.
Starch - Starke 11/2010; 62(12):676 - 685. · 1.24 Impact Factor
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ABSTRACT: The kinetics, energetics, and structure of Cyclolinopeptide A binding with Human Serum Albumin were investigated with surface plasmon resonance and circular dichroism. The complex is formed through slow recognition kinetics that is temperature sensitive in the range of 20°C-37°C. The overall reaction was observed to be endothermic (ΔH = 204 kJ mol(-1)) and entropy driven (ΔS = 746 J mol(-1)K(-1)) with overall small changes to the tertiary structure.
Journal of Biomedicine and Biotechnology 01/2010; 2010:737289. · 2.44 Impact Factor
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ABSTRACT: The Na(+) cation in the title compound, [Na(C(3)H(7)O(3))](n) or Na[H(2)gl], is coordinated by five O atoms leading to a distorted trigonal-bipyramidal geometry. The negatively charged O atom of the glycerolate anion is in an equatorial position, and the O atom of the hydroxo group, attached to the secondary C atom, occupies an axial position completing a five-membered non-planar chelate ring; this defines the asymmetric unit. The Na(+) cation is coordinated by three other symmetry-related monodentate H(2)gl(-) ligands, so that each H(2)gl(-) ligand is bonded to four Na(+) ions. The H(2)gl(-) ligands are connected via strong O-H⋯O hydrogen bonds and these, together with the Na⋯O inter-connections, are responsible for the formation of polymeric sheets which propagate in the directions of the b and c axes.
Acta Crystallographica Section E Structure Reports Online 01/2010; 66(Pt 6):m634-5. · 0.35 Impact Factor
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ABSTRACT: Carbon nanotube has a high potential to be used as a biosensor and drug carrier. However, its binding behavior with proteins needs to be studied before the full potential of carbon nanotube in biological studies can be realized. Although many studies have been conducted to characterize the affinity of functionalized carbon nanotube to various types of proteins, our present study for the first time reported that hemoglobin can bind with non-functionalized carbon nanotube, and this binding can be identified by Raman spectrum. Further, this binding has not changed Raman luminescence with specific excitation and emission wavelengths. The immediate application of these findings is to use non-functionalized carbon nanotube as a biosensor to measure H(2)S in blood in which hemoglobin takes about 37% of the total blood volume. Other potential uses of non-functionalized carbon nanotube to bind selective groups of proteins are also hinted.
Colloids and Surfaces B Biointerfaces 09/2008; 65(1):146-9. · 3.46 Impact Factor
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ABSTRACT: Iron (Fe) is a ubiquitous redox-active element essential for most life. The formation of localized cell wall appositions, the oxidative burst and the production of pathogenesis-related proteins are hallmarks of plant defense responses. Here, we report that iron is a central mediator linking these three phenomena. We show that in response to pathogen attack, reactive Fe3+, but not Fe2+, is deposited at cell wall appositions where it accumulates and mediates the oxidative burst. We provide evidence that the bulk secretion of Fe3+ provoked by pathogen attack leads to intracellular iron depletion, and that H2O2 itself induces ATP-dependent intracellular iron efflux. Finally, we demonstrate that this intracellular iron depletion promotes the transcription of pathogenesis-related genes in concert with H2O2. This work identifies iron as an underlying factor associated with the oxidative burst and regulating cereal defenses, and establishes links between disease-related iron homeostasis in plants and animals.
Journal of Cell Science 03/2007; 120(Pt 4):596-605. · 6.11 Impact Factor
