Crystal structure of hydroxynitrile lyase from Sorghum bicolor in complex with the inhibitor benzoic acid: a novel cyanogenic enzyme.

The crystal structure of the hydroxynitrile lyase from Sorghum bicolor (SbHNL) in complex with the inhibitor benzoic acid has been determined at 2.3 A resolution and refined to a crystallographic R-factor of 16.5%.

Structure determinants of substrate specificity of hydroxynitrile lyase from Manihot esculenta.

Tryptophan 128 of hydroxynitrile lyase of Manihot esculenta (MeHNL) covers a significant part of a hydrophobic channel that gives access to the active site of the enzyme. This residue was therefore substituted in the mutant MeHNL-W128A by alanine to study its importance for the substrate specificity of the enzyme. Wild-type MeHNL and MeHNL-W128A showed comparable activity on the natural substrate acetone cyanohydrin (53 and 40 U/mg, respectively).

Mechanistic aspects of cyanogenesis from active-site mutant Ser80Ala of hydroxynitrile lyase from Manihot esculenta in complex with acetone cyanohydrin.

The structure and function of hydroxynitrile lyase from Manihot esculenta (MeHNL) have been analyzed by X-ray crystallography and site-directed mutagenesis. The crystal structure of the MeHNL-S80A mutant enzyme has been refined to an R-factor of 18.0% against diffraction data to 2.

Structure of hydroxynitrile lyase from Manihot esculenta in complex with substrates acetone and chloroacetone: implications for the mechanism of cyanogenesis.

The crystal structures of hydroxynitrile lyase from Manihot esculenta (MeHNL) complexed with the native substrate acetone and substrate analogue chloroacetone have been determined and refined at 2.2 A resolution. The substrates are positioned in the active site by hydrogen-bond interactions of the carbonyl O atom with Thr11 OG, Ser80 OG and, to a lesser extent, Cys81 SG.

The mechanism of aconitase: 1.8 A resolution crystal structure of the S642a:citrate complex.

The crystal structure of the S642A mutant of mitochondrial aconitase (mAc) with citrate bound has been determined at 1.8 A resolution and 100 K to capture this binding mode of substrates to the native enzyme. The 2.

Crystallization and preliminary x-ray diffraction analysis of hydroxynitrile lyase from cassava (Manihot esculenta).

Hydroxynitrile lyase from M. esculenta (cassava) was crystallized in two different crystal forms by the hanging-drop vapour-diffusion method. Crystals of form I were obtained from a mixture of polyethylene glycol 8000 and 2-methyl-2,4-pentanediol, and belong to the tetragonal space group P41212 or its enantiomorph P43212, with unit-cell parameters a = b = 105.

The reaction of fluorocitrate with aconitase and the crystal structure of the enzyme-inhibitor complex.

It has been known for many years that fluoroacetate and fluorocitrate when metabolized are highly toxic, and that at least one effect of fluorocitrate is to inactivate aconitase. In this paper we present evidence supporting the hypothesis that the (-)-erythro diastereomer of 2-fluorocitrate acts as a mechanism based inhibitor of aconitase by first being converted to fluoro-cis-aconitate, followed by addition of hydroxide and with loss of fluoride to form 4-hydroxy-trans-aconitate (HTn), which binds very tightly, but not covalently, to the enzyme. Formation of HTn by these reactions is in accord with the working model for the enzyme mechanism.

Crystallographic studies and preliminary X-ray investigation of (S)-p-hydroxy-mandelonitrile lyase from Sorghum bicolor (L.).

(S)-p-Hydroxy-mandelonitrile lyase from Sorghum bicolor has been crystallized in three different forms using the hanging-drop vapor-diffusion technique. Crystal form I is obtained from 1.4 M (NH(4))(2)SO(4) in 100 mM Na-acetate, pH 4.

Steric and conformational features of the aconitase mechanism.

Crystal structures of mitochondrial aconitase with alpha-methylisocitrate and with sulfate bound have been solved and refined at 2.0 A resolution with R factors of 18.2 and 16.

Crystallization and preliminary X-ray diffraction studies of mandelonitrile lyase from almonds.

Single crystals of three different isoenzymes of (R)-(+) mandelonitrile lyase (hydroxynitrile lyase) from almonds (Prunus amygdalus) have been obtained by hanging drop vapor diffusion using polyethylene glycol 4000 and isopropanol as co-precipitants. The crystals belong to the monoclinic space group P2(1) with unit cell parameters a = 69.9, b = 95.

Crystal structures of aconitase with trans-aconitate and nitrocitrate bound.

Crystal structures of mitochondrial aconitase with the inhibitors trans-aconitate and nitrocitrate bound to the [4Fe-4S] cluster have been solved and refined at 2.05 A resolution with R-factors of 0.168 and 0.

Automated docking in crystallography: analysis of the substrates of aconitase.

Automated docking of substrates to proteins of known structure aids the process of crystallographic analysis in two ways. First, automated docking can be used to generate a small number of starting models for substrates using only protein coordinates from an early stage of refinement. Second, automated docking provides a method for exploring aspects of catalysis that are inaccessible to crystallography by postulating binding modes of catalytic intermediates.

Crystal structures of aconitase with isocitrate and nitroisocitrate bound.

The crystal structures of mitochondrial aconitase with isocitrate and nitroisocitrate bound have been solved and refined to R factors of 0.179 and 0.161, respectively, for all observed data in the range 8.

Studies on the domain structure of the Salmonella typhimurium AraC protein.

The Salmonella typhimurium araC gene product is known to be susceptible to proteolytic degradation. Limited cleavage by trypsin, kallikrein, elastase and pronase E yields stable fragments comprising approximately the N-terminal two thirds of the AraC protein. These fragments have in common the ability to dimerize in solution and to bind L-arabinose and D-fucose.

Three-dimensional structure of d(GGGATCCC) in the crystalline state.

The structure of the self-complementary octamer d(GGGATCCC) has been analysed by single crystal X-ray diffraction methods at a nominal resolution of 2.5 A. With acceptable stereochemistry of the model the crystallographic R factor was 16.

Crystal structure analysis of an A-DNA fragment at 1.8 A resolution: d(GCCCGGGC).

Single crystals of the self-complementary octadeoxyribonucleotide d(GCCCGGGC) have been analysed by X-ray diffraction methods at a resolution of 1.8 A. The tetragonal unit cell of space group P4(3)2(1)2 has dimensions of a = 43.

A two-dimensional NMR study of the solution structure of a DNA dodecamer comprising the concensus sequence for the specific DNA-binding sites of the glucocorticoid receptor protein.

A two-dimensional 500-MHz 1H-NMR study on the non-self-complementary double-stranded DNA dodecamer 5'd(C-C-A-G-A-A-C-A-G-T-G-G)5'd(C-C-A-C-T-G-T-T-C-T-G-G), is presented. This oligonucleotide contains the consensus octanucleotide sequence 5'd(A-G-A-A-C-A-G-T) for the specific DNA-binding sites of the glucocorticoid receptor protein [Payvar, F. et al.