title: Establishment of glutamine synthetase of Mycobacterium smegmatis as a protein acetyltransferase utilizing polyphenolic acetates as the acetyl group donors.
abstract: 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 M(r) 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.
authors.affiliation: Department of Biochemistry and Microbiology, University of Delhi, Delhi-1100 07, India.
authors.forename: Garima
authors.initials: G
authors.lastname: Gupta
authors.forename: Anil Singh
authors.initials: AS
authors.lastname: Baghel
authors.forename: Seema
authors.initials: S
authors.lastname: Bansal
authors.forename: Tapesh Kumar
authors.initials: TK
authors.lastname: Tyagi
authors.forename: Ranju
authors.initials: R
authors.lastname: Kumari
authors.forename: Neeraj Kumar
authors.initials: NK
authors.lastname: Saini
authors.forename: Prija
authors.initials: P
authors.lastname: Ponnan
authors.forename: Ajit
authors.initials: A
authors.lastname: Kumar
authors.forename: Mridula
authors.initials: M
authors.lastname: Bose
authors.forename: Daman
authors.initials: D
authors.lastname: Saluja
authors.forename: Shamkant Anant
authors.initials: SA
authors.lastname: Patkar
authors.forename: Virinder Singh
authors.initials: VS
authors.lastname: Parmar
authors.forename: Hanumantharao Guru
authors.initials: HG
authors.lastname: Raj
mesh_terms: D000085:Acetates / Q000378:metabolism*; D000107:Acetylation; D000123:Acetyltransferases / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D003374:Coumarins / Q000378:metabolism; D005419:Flavonoids / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000737:chemistry* / Q000378:metabolism; D020102:Mycobacterium smegmatis / Q000201:enzymology* / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D059808:Polyphenols; D013329:Structure-Activity Relationship
chemical_list: C114369:7,8-diacetoxy-4-methylcoumarin; D000085:Acetates; D003374:Coumarins; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D000123:Acetyltransferases; D005974:Glutamate-Ammonia Ligase