title: Characterization of protein acyltransferase function of recombinant purified GlnA1 from Mycobacterium tuberculosis: a moon lighting property.
abstract: The protein acetyltransferase (MTAase) function of glutamine synthetase of Mycobacterium smegmatis was established earlier. In this paper, studies were undertaken to examine MTAase function of recombinant glutamine synthetase (rGlnA1) of Mycobacterium tuberculosis, which showed >80% similarity with M. smegmatis GlnA. The specificity of MTAase to several acyl derivative of coumarins was examined. The results clearly indicated that MTAase exhibited differential specificities to several acyloxycoumarins. Further, MTAase was also found capable of transferring propionyl and butyryl groups from propoxy and butoxy derivatives of 4-methylcoumarin. These observations characterized MTAase in general as a protein acyltransferase. MTAase catalyzed acetylation of GST by 7,8-diacetoxy-4-methylcoumarin (DAMC), a model acetoxy coumarin was confirmed by MALDI-TOF-MS as well as western blot analysis using acetylated lysine polyclonal antibody. In order to validate the active site of rGlnA1 for TAase activity, effect of DAMC and L-methionine-S-sulfoximine (MSO) on GS and TAase activity of rGlnA1 were studied. The results indicated that the active sites of GS and TAase were found different. Acetyl CoA, a universal biological acetyl group donor, was also found to be a substrate for MTAase. These results appropriately characterize glutamine synthetase of Mtb exhibiting transacylase action as a moonlighting protein.
authors.affiliation: Department of Biochemistry, VP Chest Institute, University of Delhi, Delhi, India.
authors.forename: Anil S
authors.initials: AS
authors.lastname: Baghel
authors.forename: Rashmi
authors.initials: R
authors.lastname: Tandon
authors.forename: Garima
authors.initials: G
authors.lastname: Gupta
authors.forename: Ajit
authors.initials: A
authors.lastname: Kumar
authors.forename: Raman K
authors.initials: RK
authors.lastname: Sharma
authors.forename: Neha
authors.initials: N
authors.lastname: Aggarwal
authors.forename: Abha
authors.initials: A
authors.lastname: Kathuria
authors.forename: Neeraj K
authors.initials: NK
authors.lastname: Saini
authors.forename: Mridula
authors.initials: M
authors.lastname: Bose
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Prasad
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Mahendra
authors.initials: M
authors.lastname: Nath
authors.forename: Virinder S
authors.initials: VS
authors.lastname: Parmar
authors.forename: Hanumantharao G
authors.initials: HG
authors.lastname: Raj
mesh_terms: D000105:Acetyl Coenzyme A / Q000378:metabolism; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D020134:Catalytic Domain; D003374:Coumarins / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism*; D020102:Mycobacterium smegmatis / Q000201:enzymology / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D003374:Coumarins; D011994:Recombinant Proteins; D000105:Acetyl Coenzyme A; D000123:Acetyltransferases; C062782:protein acyltransferase; C081173:glutamine synthetase I; D005974:Glutamate-Ammonia Ligase