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Deciphering crucial threonines towards functionality of an essential eukaryotic‐type Ser/Thr kinase from M. tuberculosis (802.1)
Author(s) -
Ravala Sandeep,
Yadav Ghanshyam,
Chakraborti Pradip
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.802.1
Subject(s) - kinase , threonine , biology , protein kinase domain , phosphorylation , transmembrane protein , function (biology) , transmembrane domain , amino acid , biochemistry , microbiology and biotechnology , gene , serine , mutant , receptor
PknA is an essential Ser/Thr kinase in mycobacteria and is involved in several physiological processes including cell division and cell wall biosynthesis. Previous results of phospho‐amino acid analysis through western blotting established that PknA predominantly phosphorylates at threonines. Structurally, PknA comprises of four domains, spanning catalytic, juxtamembrane, transmembrane and extracellular domains. Unlike other eukaryotic‐type Ser/thr kinases in M. tuberculosis, PknA catalytic domain was found to be devoid of autophosphorylating ability and only in conjunction with juxtamembrane, it exhibited catalytic activity. Therefore, the focus of the study was to delineate the minimum region of juxtamembrane required for PknA function so that crucial threonines involved in its phosphorylation could be deciphered. Using mutational analysis and E.coli based phenotypic assay as tools, we report here the essentiality of six residues from juxtamembrane region for the kinase activity exhibited by PknA. Furthermore, we observed Thr‐180 and Thr‐224 along with the activation loop threonines were critical for the functionality of PknA. Grant Funding Source : Supported by CSIR Network Project