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The DNA recognition subunit of a DNA methyltransferase is predominantly a molten globule in the absence of DNA
Author(s) -
Hornby David P.,
Whitmarsh Alan,
Pinarbasi Hatice,
Kelly Sharon M.,
Price Nicholas C.,
Shore Paul,
Baldwin Geoffrey S.,
Waltho Jonathan
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)01171-0
Subject(s) - molten globule , dna , dna methyltransferase , protein subunit , chemistry , biochemistry , circular dichroism , dna methylation , cytosine , biophysics , methyltransferase , biology , methylation , gene , gene expression
Enzyme‐catalysed DNA methylation provides an opportunity for the modulation of protein‐DNA recognition in biological systems. Recently we have demonstrated that the smaller of the two subunits of the heterodimeric, cytosine‐specific DNA methyltransferase, M. Aqu I, is largely responsible for sequence‐specific DNA recognition. Here we present evidence from a series of NMR, fluorescence and circular dichroism spectroscopy experiments that the DNA binding subunit of M. Aqu I has the characteristics of a molten globule in the absence of the catalytic machinery. In this metastable state this subunit retains its ability to bind DNA in a sequence‐specific manner. We believe this finding offers an insight into the structural flexibility which underpins the mechansim of action of these enzymes, and may provide a possible biological role for molten globules in protein function.