Purification and characterization of anthranilate synthase component I (TrpE) from Mycobacterium tuberculosis H37Rv

Protein Expr Purif. 2009 Mar;64(1):8-15. doi: 10.1016/j.pep.2008.09.020. Epub 2008 Oct 10.

Abstract

The emergence of multi-drug resistant (MDR) strains of Mycobacterium tuberculosis is the main reason why tuberculosis (TB) continues to be a major health problem worldwide. It is urgent to discover novel anti-mycobacterial agents based on new drug targets for the treatment of TB, especially MDR-TB. Tryptophan biosynthetic pathway, which is essential for the survival of M. tuberculosis and meanwhile absent in mammals, provides potential anti-TB drug targets. One of the promising drug targets in this pathway is anthranilate synthase component I (TrpE), whose role is to catalyze the conversion of chorismate to anthranilate using ammonia as amino source. In order to get a deep understanding of TrpE, a study on purification and characteristic identification of TrpE is required. In this work, the putative trpE gene of M. tuberculosis H37Rv was expressed as a fusion protein with a 6x His-tag on the N-terminal (His-TrpE) in Escherichia coli. The recombinant TrpE protein was successfully purified and then its enzymatic characteristics were analyzed. The native TrpE without His-tag was obtained by removal of the N-terminal fusion partner of His-TrpE using enterokinase. It was found that N-terminal fusion partner had little influence on TrpE catalytic activity. In addition, the key residues related to enzyme catalytic activity and that involved in l-tryptophan inhibition were predicted in the structure of M. tuberculosis H37Rv TrpE. These results would be beneficial to the designing of novel anti-TB drugs with high potency and selectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Motifs
  • Amino Acid Sequence
  • Anthranilate Synthase / chemistry
  • Anthranilate Synthase / genetics
  • Anthranilate Synthase / isolation & purification*
  • Anthranilate Synthase / metabolism
  • Anti-Bacterial Agents / pharmacology
  • Antitubercular Agents / pharmacology
  • Conserved Sequence
  • Drug Design
  • Drug Resistance, Multiple, Bacterial / drug effects
  • Drug Resistance, Multiple, Bacterial / genetics
  • Escherichia coli / genetics
  • Genes, Bacterial / drug effects
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Weight
  • Mycobacterium tuberculosis / enzymology*
  • Mycobacterium tuberculosis / genetics
  • Protein Conformation
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Tuberculosis / genetics
  • Tuberculosis / therapy
  • Tuberculosis, Multidrug-Resistant / genetics

Substances

  • Anti-Bacterial Agents
  • Antitubercular Agents
  • Recombinant Proteins
  • Anthranilate Synthase