Characterization of the putative tryptophan synthase β-subunit from Mycobacterium tuberculosis

Characterization of the putative tryptophan synthase β-subunit from Mycobacterium

tuberculosis

Hongbo Shen;Yanping Yang;Feifei Wang;Ying Zhang;Naihao Ye;Shengfeng Xu;Honghai Wang

【期刊名称】《生物化学与生物物理学报：英文版》 【年(卷),期】2009(041)005

【摘要】The increasing emergence of drug-resistant tuberculosis (TB)poses a serious threat to the control of this disease.It is in urgent need to develop new TB drugs.Tryptophan biosynthetic pathway plays an important role in the growth and replication of Mycobacterium tuberculosis(Mtb).The β-subunit of tryptophan synthase(TrpB)catalyzes the last step of the tryptophan biosynthetic pathway,and it might be a potential

target

for

TB

drug

design.In

this

study,we

overexpressed,purified,and characterized the putative TrpB-encoding gene Rv1612 in Mtb H37Rv.Results showed that Mtb His-TrpB optimal enzymatic activity is at pH 7.8 with 0.15 M Na+or 0.18 M Mg2+ at 37℃.Structure analysis indicated that Mtb TrpB exhibited a typical β/α barrel structure.The amino acid residues believed to interact with the enzyme cofactor pyridoxal-5'-phosphate were predicted by homology modeling and structure alignment.The role of these residues in catalytic activity of the Mtb His-TrpB was confirmed by site-directed