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Author Notes:

Correspondence should be addressed to: X.C. (xcheng@emory.edu)

We thank beamline staff for help with X-ray data collection at beamlines X12C, X25 and X26C in the facilities of the National Synchrotron Light Source, Brookhaven National Laboratory, R.M. Blumenthal (Medical College of Ohio) for comments and M. Churchill (University of Colorado) for discussion.

The authors declare that they have no competing financial interests.

Subjects:

Research Funding:

US Public Health Services grants to S.H and X.C.

Georgia Research Alliance

Structure of the bacteriophage T4 DNA adenine methyltransferase

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Journal Title:

Nature Structural Biology

Volume:

Volume 10, Number 10

Publisher:

, Pages 849-855

Type of Work:

Article | Post-print: After Peer Review

Abstract:

DNA-adenine methylation at certain GATC sites plays a pivotal role in bacterial and phage gene expression as well as bacterial virulence. We report here the crystal structures of the bacteriophage T4Dam DNA adenine methyltransferase (MTase) in a binary complex with the methyl-donor product S-adenosyl-L-homocysteine (AdoHcy) and in a ternary complex with a synthetic 12-bp DNA duplex and AdoHcy. T4Dam contains two domains: a seven-stranded catalytic domain that harbors the binding site for AdoHcy and a DNA binding domain consisting of a five-helix bundle and a β-hairpin that is conserved in the family of GATC-related MTase orthologs. Unexpectedly, the sequence-specific T4Dam bound to DNA in a nonspecific mode that contained two Dam monomers per synthetic duplex, even though the DNA contains a single GATC site. The ternary structure provides a rare snapshot of an enzyme poised for linear diffusion along the DNA.

Copyright information:

© 2003 Nature Publishing Group

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