The DNA binding affinity of HhaI methylase is increased by a single amino acid substitution in the catalytic center

Mi, S., Roberts, R. J. (May 1993) The DNA binding affinity of HhaI methylase is increased by a single amino acid substitution in the catalytic center. Nucleic Acids Res, 21 (10). pp. 2459-64. ISSN 0305-1048 (Print)

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URL: http://www.ncbi.nlm.nih.gov/pubmed/8506140

DOI: 10.1093/nar/21.10.2459

Abstract

The HhaI methyltransferase recognizes the sequence GCGC and transfers a methyl group to C5 of the first cytosine residue. All m5C-methyltransferases contain a highly conserved sequence motif called the P-C motif. The cysteine residue of this motif is involved in catalysis by forming a covalent bond with the 6-position of cytosine prior to methyl group transfer. For the EcoRII methyltransferase, it has been shown that substitution of this catalytic cysteine by glycine is cytotoxic to E.coli cells expressing the mutant methyltransferase (Wyszynski et al. Nucl. Acids Res. 20: 319, 1992). We now show that this observation can be extended to the HhaI system and suggest that the cytotoxicity is due to abnormally tight DNA binding by the mutant methyltransferase, which probably interferes with replication or transcription.

Item Type:	Paper
Uncontrolled Keywords:	Amino Acid Sequence Base Sequence Binding Sites Catalysis DNA/chemistry/ metabolism Deoxyribonucleases, Type II Site-Specific Escherichia coli/genetics Glycine Kinetics Molecular Sequence Data Mutagenesis, Site-Directed Plasmids Research Support, U.S. Gov't, Non-P.H.S. Research Support, U.S. Gov't, P.H.S. Site-Specific DNA Methyltransferase (Cytosine-Specific)/ chemistry/genetics/ metabolism Structure-Activity Relationship
Subjects:	bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > DNA binding protein bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > methyltransferase
CSHL Authors:	Roberts, Richard J. Mi, Sha
Communities:	CSHL labs > Roberts lab
Depositing User:	Matt Covey
Date:	25 May 1993
Date Deposited:	08 Apr 2016 16:35
Last Modified:	08 Nov 2017 16:11
PMCID:	PMC309547
Related URLs:	Publisher
URI:	https://repository.cshl.edu/id/eprint/32582

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