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Characterization of a eukaryotic type serine/threonine protein kinase and protein phosphatase of Streptococcus pneumoniae and identification of kinase substrates
Author(s) -
Nováková Linda,
Sasková Lenka,
Pallová Petra,
Janeček Jiří,
Novotná Jana,
Ulrych Aleš,
Echenique Jose,
Trombe MarieClaude,
Branny Pavel
Publication year - 2005
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/j.1742-4658.2005.04560.x
Subject(s) - biochemistry , biology , protein kinase a , phosphatase , kinase , c raf , threonine , phosphorylation , serine , microbiology and biotechnology , cyclin dependent kinase 2
Searching the genome sequence of Streptococcus pneumoniae revealed the presence of a single Ser/Thr protein kinase gene stkP linked to protein phosphatase phpP . Biochemical studies performed with recombinant StkP suggest that this protein is a functional eukaryotic‐type Ser/Thr protein kinase. In vitro kinase assays and Western blots of S. pneumoniae subcellular fractions revealed that StkP is a membrane protein. PhpP is a soluble protein with manganese‐dependent phosphatase activity in vitro against a synthetic substrate RRA(pT)VA. Mutations in the invariant aspartate residues implicated in the metal binding completely abolished PhpP activity. Autophosphorylated form of StkP was shown to be a substrate for PhpP. These results suggest that StkP and PhpP could operate as a functional pair in vivo . Analysis of phosphoproteome maps of both wild‐type and stkP null mutant strains labeled in vivo and subsequent phosphoprotein identification by peptide mass fingerprinting revealed two possible substrates for StkP. The evidence is presented that StkP can phosphorylate in vitro phosphoglucosamine mutase GlmM which catalyzes the first step in the biosynthetic pathway leading to the formation of UDP‐ N ‐acetylglucosamine, an essential common precursor to cell envelope components.