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Probing the biological role a poor Km plays in the processivity and temporal control of CcrM (549.9)
Author(s) -
Woodcock Clayton,
Reich Norbert
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.549.9
Subject(s) - caulobacter crescentus , biology , processivity , dnmt1 , prokaryote , dna methylation , eukaryotic cell , dna , gene silencing , methyltransferase , microbiology and biotechnology , dna replication , genetics , methylation , cell , gene , cell cycle , gene expression
Caulobacter crescentus is a model prokaryote involving asymmetric division which requires stringent temporal and spatial control of gene regulation attained through epigenetic silencing. The Cell cycle regulated Methyltransferase, CcrM plays as an essential role in this process, and is tightly regulated during cell division. The essential methylation of the entire X bp Caulobacter genome requires a highly efficient enzyme, and two prior reports are conflicting on CcrM’s methylation mechanism. We provide a rigorous test of the enzyme’s ability to methylate multiple recognition sites (processive catalysis) and show that indeed, the enzyme acts processively. Surprisingly, we also show that CcrM has an unusually poor affinity for its DNA substrates in comparison to other bacterial and eukaryotic DNA methyltransferases. We suggest that this poor DNA affinity may serve a biological role since CcrM is rapidly proteolyzed by Lon protease in vivo. We are currently determining if this efficient proteolysis occurs because CcrM is poorly associated with DNA.