title: Transient DNA binding by a proteolytic peptide from m5C-DNA methyltransferase MspI.
abstract: A peptide fragment (p26) generated as a result of limited tryptic proteolysis of methyltransferase MspI retains transient but non-specific DNA binding capability. The transient DNA binding by p26 was characterized with respect to physicochemical factors. Limited proteolysis was performed to probe gross structural deviation from the reported two-domain organization for m5C-MTases, in light of topoisomerase activity shown by MspI, resulted in two peptide fragments; a large fragment p26 and a small fragment p18, consistent with the other reported m5C-MTase structures. The purified large peptide fragment p26, spans between 6 and 251 in the amino acid sequence of M.MspI. The peptide p26 does not bind S-adenosylmethionine, although in the intact protein the AdoMet binding region can be mapped to a region in the protein that is present in this peptide. Such transient DNA binding has not been reported for other protolytic product of any other m5C-DNA methyltransferase.
authors.affiliation: Deparment of Biochemical Engineering and Biotechnology, Indian Institute of Technology-Delhi, Hauz Khas, New Delhi 110016, India. bhattas@ccf.org
authors.forename: Sanjoy K
authors.initials: SK
authors.lastname: Bhattacharya
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Dubey
mesh_terms: D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000378:metabolism; D015257:DNA-Cytosine Methylases / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D007700:Kinetics; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000378:metabolism; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D012436:S-Adenosylmethionine; C029641:DNA modification methylase HpaII; D015257:DNA-Cytosine Methylases; D014357:Trypsin