Biomedical subjects

M V Petoukhov

Publications and source records attributed to M V Petoukhov.

3 recordsLinked to original sources

PubMed2003

Structural characterization of T-protein of the Escherichia coli glycine cleavage system by X-ray small angle scattering.

T-protein, one of the components of the glycine cleavage complex, catalyses the formation of ammonia and methylene-tetrahydrofolate from H-protein-bound intermediate. Native T-protein of the glycine cleavage system from E. coli was efficiently purified using a combination of hydrophobic interaction, gel permeation and ion exchange chromatography. Synchrotron radiation small angle X-ray solution scattering indicates that T-protein has an extended structure in solution. A low resolution model of the protein was constructed ab initio and tentative models of the tertiary structure were built using prediction methods constrained by the scattering data.

Aminomethyltransferase↗

PubMed2001

Determination of domain structure of proteins from X-ray solution scattering.

An ab initio method for building structural models of proteins from x-ray solution scattering data is presented. Simulated annealing is employed to find a chain-compatible spatial distribution of dummy residues which fits the experimental scattering pattern up to a resolution of 0.5 nm. The efficiency of the method is illustrated by the ab initio reconstruction of models of several proteins, with known and unknown crystal structure, from experimental scattering data. The new method substantially improves the resolution and reliability of models derived from scattering data and makes solution scattering a useful technique in large-scale structural characterization of proteins.

Algorithms↗

PubMed2000

Crystal versus solution structures of thiamine diphosphate-dependent enzymes.

The quaternary structures of the thiamine diphosphate-dependent enzymes transketolase (EC 2.2.1.1; from Saccharomyces cerevisiae), pyruvate oxidase (EC 1.2.3.3; from Lactobacillus plantarum), and pyruvate decarboxylase (EC 4.1.1.1; from Zymomonas mobilis and brewers' yeast, the latter in the native and pyruvamide-activated forms) were examined by synchrotron x-ray solution scattering. The experimental scattering data were compared with the curves calculated from the crystallographic models of these multisubunit enzymes. For all enzymes noted above, except the very compact pyruvate decarboxylase from Z. mobilis, there were significant differences between the experimental and calculated profiles. The changes in relative positions of the subunits in solution were determined by rigid body refinement. For pyruvate oxidase and transketolase, which have tight intersubunit contacts in the crystal, relatively small modifications of the quaternary structure (root mean square displacements of 0.23 and 0.27 nm, respectively) sufficed to fit the experimental data. For the enzymes with looser contacts (the native and activated forms of yeast pyruvate decarboxylase), large modifications of the crystallographic models (root mean square displacements of 0.58 and 1.53 nm, respectively) were required. A clear correlation was observed between the magnitude of the distortions induced by the crystal environment and the interfacial area between subunits.

Artifacts↗