PMID: 2510127Oct 25, 1989Paper

Single amino acid changes that alter the DNA sequence specificity of the DNA-[N6-adenine] methyltransferase (Dam) of bacteriophage T4

Nucleic Acids Research
Z MinerS Hattman

Abstract

Bacteriophage T4 codes for a DNA-[N6-adenine] methyltransferase (Dam) which recognizes primarily the sequence GATC in both cytosine- and hydroxymethylcytosine-containing DNA. Hypermethylating mutants, damh, exhibit a relaxation in sequence specificity, that is, they are readily able to methylate non-canonical sites. We have determined that the damh mutation produces a single amino acid change (Pro126 to Ser126) in a region of homology (III) shared by three DNA-adenine methyltransferases; viz, T4 Dam, Escherichia coli Dam, and the DpnII modification enzyme of Streptococcus pneumoniae. We also describe another mutant, damc, which methylates GATC in cytosine-containing DNA, but not in hydroxymethylcytosine-containing DNA. This mutation also alters a single amino acid (Phe127 to Val127). These results implicate homology region III as a domain involved in DNA sequence recognition. The effect of several different amino acids at residue 126 was examined by creating a polypeptide chain terminating codon at that position and comparing the methylation capability of partially purified enzymes produced in the presence of various suppressors. No enzyme activity is detected when phenylalanine, glutamic acid, or histidine is inserted at posit...Continue Reading

References

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Citations

May 25, 1991·Nucleic Acids Research·G G Wilson
Aug 11, 1991·Nucleic Acids Research·J A BanasA Progulske-Fox
Jul 11, 1993·Nucleic Acids Research·J B GuyotW Guschlbauer
Oct 14, 2008·Journal of Bacteriology·Edit TímárAntal Kiss
Mar 11, 2003·Microbiology and Molecular Biology Reviews : MMBR·Eric S MillerWolfgang Rüger
Aug 26, 2003·Nature Structural Biology·Zhe YangXiaodong Cheng
Jun 16, 2004·Progress in Nucleic Acid Research and Molecular Biology·Stanley Hattman, Ernst G Malygin
Sep 27, 2000·Biochimica Et Biophysica Acta·T FriedrichA Jeltsch

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