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

Research output: Contribution to journalArticlepeer-review

Abstract

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 Mg 2+ at 37°C. 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 mutagenesis. These results provided reassuring structural information for drug design based on TrpB.

Original languageEnglish (US)
Article numbergmp017
Pages (from-to)379-388
Number of pages10
JournalActa Biochimica et Biophysica Sinica
Volume41
Issue number5
DOIs
StatePublished - May 2009

Keywords

  • Active site
  • Enzyme activity
  • Mycobacterium tuberculosis
  • Site-directed mutation
  • Tryptophan synthase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry

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