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The putative compatible solute‐binding protein ProX from Mycobacterium tuberculosis H37Rv: biochemical characterization and crystallographic data
Author(s) -
Zhao Jian-Hong,
Chen Jiang-Huai,
Wang Yong,
Wang Zhi-Ping,
He Yong-Xing
Publication year - 2018
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 37
ISSN - 2053-230X
DOI - 10.1107/s2053230x18003771
Subject(s) - dissociation constant , chemistry , phloretin , crystallography , mycobacterium tuberculosis , polyethylene glycol , prox , molecule , solvent , binding site , stereochemistry , biochemistry , organic chemistry , medicine , tuberculosis , receptor , pathology , carbon monoxide , catalysis
In Mycobacterium tuberculosis , the proX gene encodes a putative compatible solute‐binding protein (MtProX). However, it was found through sequence alignment that the MtProX protein has very different ligand‐binding residues compared with other compatible solute‐binding proteins, implying that MtProX may bind to ligands that are as yet uncharacterized. In this work, it was demonstrated that MtProX binds to polyphenols such as phloretin, monoacetylphloroglucinol and 2,4‐dihydroxyacetophloroglucinol with dissociation constants between 20 and 70 µ M . Crystals of MtProX were obtained using a precipitant consisting of 0.2 M NaCl, 0.1 M Tris pH 8.5, 25%( w / v ) polyethylene glycol 3350. The crystals diffracted to 2.10 Å resolution and belonged to space group P 4 3 2 1 2, with unit‐cell parameters a = b = 90.17, c = 161.92 Å, α = β = γ = 90.0°. Assuming the presence of two MtProX molecules in the asymmetric unit, the Matthews coefficient was calculated to be 2.74 Å 3 Da −1 , which corresponds to a solvent content of 55%.