Establishment of glutamine synthetase of Mycobacterium smegmatis as a protein acetyltransferase utilizing polyphenolic acetates as the acetyl group donors

Garima Gupta, Anil Singh Baghel, Seema Bansal, Tapesh Kumar Tyagi, Ranju Kumari, Neeraj Kumar Saini, Prija Ponnan, Ajit Kumar, Mridula Bose, Daman Saluja, Shamkant Anant Patkar, Virinder Singh Parmar, Hanumantharao Guru Raj

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Acetoxy Drug: Protein Transacetylase (TAase) mediating the transfer of acetyl group(s) from polyphenolic acetates (PA) to certain functional proteins in mammalian cells was identified by our earlier investigations. TAase activity was characterized in the cell lysates of Mycobacterium smegmatis and the purified protein was found to have Mr 58,000. TAase catalysed protein acetylation by a model acetoxy drug 7,8-diacetoxy-4-methylcoumarin (DAMC) was established by the demonstration of immunoreactivity of the acetylated target protein with an anti-acetyllysine antibody. The specificity of the TAase of M. smegmatis (MTAase) to various acetoxycoumarins was found to be in the order DAMC > 7-AMC > 6-AMC > 4-AC > 3-AC > ABP. Also, the N-terminal sequence of purified MTAase was found to perfectly match with glutamine synthetase (GS) of M. smegmatis. The identity of MTAase with GS was confirmed by the observation that the purified MTAase as well as the purified recombinant GS exhibited all the properties of GS. The finding that purified Escherichia coli GS was found to have substantial TAase activity highlighted the TAase function of GS in other bacteria. These results conclusively established for the first time the protein acetyltransferase function of GS of M. smegmatis.

Original languageEnglish (US)
Pages (from-to)709-715
Number of pages7
JournalJournal of Biochemistry
Issue number6
Publication statusPublished - Dec 1 2008



  • Glutamine synthetase
  • Mycobacterium smegmatis
  • Polyphenolic acetate
  • Protein acetylation
  • Transacetylase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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