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Investigating the role of the C‐terminal domain in McsB
Author(s) -
Graham James,
Fraga Dean
Publication year - 2008
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.22.1_supplement.1054.3
Subject(s) - autophosphorylation , biochemistry , protein kinase domain , phosphotransferase , chemistry , allosteric regulation , kinase , bacillus subtilis , tyrosine kinase , microbiology and biotechnology , operon , phosphorylation , protein kinase a , enzyme , biology , mutant , signal transduction , genetics , gene , bacteria
McsB is a recently described prokaryotic protein tyrosine kinase found in Bacillus subtilis. In addition to an autophosphorylation activity, McsB can be further induced to phosphorylate other targets upon binding a second protein, McsA, encoded in the same operon as McsB. McsB is a structurally unique tyrosine kinase in that its N‐terminus corresponds to a guanidine‐phosphotransferase domain and is critical for kinase activity. However, the adjacent C‐terminal domain is not homologous to other protein domains and its role in McsB protein kinase activity is unknown. We used a series of deletion mutants to determine what potions of the C‐terminal domain were important for kinase activity and/or its regulation by McsA. Our hypothesis was that the C‐terminal domain regulated activity by either blocking access to the active site by acting as a pseudo substrate, or by holding the enzyme in a conformationally inactive state until bound by McsA. Preliminary results indicate that the deletion mutations greatly reduce or abolish the inducible enzymatic activity thus supporting a model that this region has an important role to play in the inducible catalytic activity but not in autophosphorylation activty.