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Selective targeting of the conserved active site cysteine of Mycobacterium tuberculosis methionine aminopeptidase with electrophilic reagents
Author(s) -
Reddi Ravikumar,
Arya Tarun,
Kishor Chandan,
Gumpena Rajesh,
Ganji Roopa J.,
Bhukya Supriya,
Addlagatta Anthony
Publication year - 2014
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.12847
Subject(s) - cysteine , active site , biochemistry , chemistry , mutagenesis , mycobacterium tuberculosis , cysteine metabolism , enzyme , stereochemistry , mutant , tuberculosis , gene , medicine , pathology
Methionine aminopeptidases (Met AP s) cleave initiator methionine from ~ 70% of the newly synthesized proteins in every living cell, and specific inhibition or knockdown of this function is detrimental. Met AP s are metalloenzymes, and are broadly classified into two subtypes, type I and type II . Bacteria contain only type I Met AP s, and the active site of these enzymes contains a conserved cysteine. By contrast, in type II enzymes the analogous position is occupied by a conserved glycine. Here, we report the reactivity of the active site cysteine in a type I Met AP , Met AP 1c, of Mycobacterium tuberculosis ( Mt Met AP 1c) towards highly selective cysteine‐specific reagents. The authenticity of selective modification of Cys105 of Mt Met AP 1c was established by using site‐directed mutagenesis and crystal structure determination of covalent and noncovalent complexes. On the basis of these observations, we propose that metal ions in the active site assist in the covalent modification of Cys105 by orienting the reagents appropriately for a successful reaction. These studies establish, for the first time, that the conserved cysteine of type I Met AP s can be targeted for selective inhibition, and we believe that this chemistry can be exploited for further drug discovery efforts regarding microbial Met AP s.