'Pseudo' domains in phage-encoded DNA methyltransferases

5-Cytosine-DNA-methyltransferases, which are found in many organisms ranging from bacteriophages to mammals, transfer a methyl group from S-adenosylmethionine to the carbon-5 of a cytosine residue in specific DNA target sequences. Some phage-encoded methyltransferases methylate more than one sequenc...

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Bibliographic Details
Published in:Nature (London) 1991-08, Vol.352 (6336), p.645-647
Main Authors: Lange, C, Jugel, A, Walter, J, Noyer-Weidner, M, Trautner, T A
Format: Article
Language:English
Subjects:
5-cytosine-DNA-methyltransferase
Amino Acid Sequence
Bacteriophages - enzymology
Binding Sites
Biochemistry
Deoxyribonucleic acid
DNA
DNA (Cytosine-5-)-Methyltransferases - chemistry
DNA (Cytosine-5-)-Methyltransferases - metabolism
DNA methyltransferase
DNA-Binding Proteins - chemistry
DNA-Binding Proteins - metabolism
DNA-Cytosine Methylases - chemistry
DNA-Cytosine Methylases - metabolism
Enzymes
Genetics
Methylation
Molecular Sequence Data
Proteins
Structure-Activity Relationship
Substrate Specificity
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Summary:5-Cytosine-DNA-methyltransferases, which are found in many organisms ranging from bacteriophages to mammals, transfer a methyl group from S-adenosylmethionine to the carbon-5 of a cytosine residue in specific DNA target sequences. Some phage-encoded methyltransferases methylate more than one sequence: these enzymes contain several independent target-recognizing domains each responsible for recognizing a different site. The amino-acid sequences of these multispecific methyltransferases reveal that some enzymes in addition carry domains that do not contribute to the enzymes' methylation potential, but strongly resemble previously identified target-recognizing domains. Here we show that introducing defined amino-acid alterations into these inactive domains endows these enzymes with additional methylation specificities. Gel retardation analysis demonstrates that these novel methylation specificities correlate with the acquisition of additional DNA-binding potential of the proteins.
ISSN:0028-0836
1476-4687
DOI:10.1038/352645a0