Hhal Methyltransferase Flips Its Target Base out of the DNA Helix

Klimasauskas, S., Kumar, S., Roberts, R. J., Cheng, X. D. (1994) Hhal Methyltransferase Flips Its Target Base out of the DNA Helix. Cell, 76 (2). pp. 357-369. ISSN 0092-8674

URL: http://www.ncbi.nlm.nih.gov/pubmed/8293469
DOI: 10.1016/0092-8674(94)90342-5

Abstract

The crystal structure has been determined at 2.8 A resolution for a chemically-trapped covalent reaction intermediate between the HhaI DNA cytosine-5-methyltransferase, S-adenosyl-L-homocysteine, and a duplex 13-mer DNA oligonucleotide containing methylated 5-fluorocytosine at its target. The DNA is located in a cleft between the two domains of the protein and has the characteristic conformation of B-form DNA, except for a disrupted G-C base pair that contains the target cytosine. The cytosine residue has swung completely out of the DNA helix and is positioned in the active site, which itself has undergone a large conformational change. The DNA is contacted from both the major and the minor grooves, but almost all base-specific interactions between the enzyme and the recognition bases occur in the major groove, through two glycine-rich loops from the small domain. The structure suggests how the active nucleophile reaches its target, directly supports the proposed mechanism for cytosine-5 DNA methylation, and illustrates a novel mode of sequence-specific DNA recognition.

Item Type: Paper
Uncontrolled Keywords: COLI THYMIDYLATE SYNTHASE CRYSTAL-STRUCTURE MACROMOLECULAR CRYSTALLOGRAPHY DETERMINES METHYLATION DIFFRACTION ANALYSIS RECOGNIZING DOMAINS MAMMALIAN NUCLEI MISMATCH REPAIR GENE-EXPRESSION MECHANISM
Subjects: bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > DNA binding protein
Investigative techniques and equipment > x ray crystallography
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date Deposited: 04 May 2015 16:06
Last Modified: 04 May 2015 16:06
Related URLs:
URI: http://repository.cshl.edu/id/eprint/31481

Actions (login required)

Administrator's edit/view item Administrator's edit/view item
CSHL HomeAbout CSHLResearchEducationNews & FeaturesCampus & Public EventsCareersGiving