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
Feb 25, 1979·Journal of Molecular Biology·B BächiV Pirrotta
Dec 1, 1977·Proceedings of the National Academy of Sciences of the United States of America·F SangerA R Coulson
Dec 15, 1978·Journal of Molecular Biology·S HattmanM Masurekar
Dec 15, 1978·Journal of Molecular Biology·J E Brooks, S Hattman
Mar 5, 1978·Journal of Molecular Biology·S HattmanA de Waard
Aug 8, 1975·Nucleic Acids Research·H van OrmondtA de Waard
Feb 28, 1988·Biochimica Et Biophysica Acta·M M Doolittle, K Sirotkin
Jul 19, 1985·Science·R M MyersT Maniatis
Dec 25, 1988·Gene·W Guschlbauer
Sep 1, 1986·Proceedings of the National Academy of Sciences of the United States of America·J NormanlyJ H Miller
Apr 1, 1967·Virology·H R Revel
Aug 1, 1971·Virology·H R Revel, S M Hattman
Jan 1, 1970·Annual Review of Genetics·H R Revel, S E Luria
Oct 1, 1970·Virology·S Hattman
Citations
May 19, 1995·Gene·V G KossykhS Hattman
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
Mar 27, 2001·Nucleic Acids Research·I MinkoV Kossykh
Oct 14, 2008·Journal of Bacteriology·Edit TímárAntal Kiss
Mar 11, 2003·Microbiology and Molecular Biology Reviews : MMBR·Eric S MillerWolfgang Rüger
Jun 17, 1998·Biological Chemistry·T FriedrichA Jeltsch
Aug 26, 2003·Nature Structural Biology·Zhe YangXiaodong Cheng
Sep 22, 2009·Journal of Molecular Biology·Sanjay ChaharAlbert Jeltsch
Dec 24, 1998·Structure·P H TranS A Lacks
May 11, 2005·Cell·John R HortonXiaodong 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