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The cell cycle-regulated DNA adenine methyltransferase CcrM opens a bubble at its DNA recognition site.

ABSTRACT: The Caulobacter crescentus cell cycle-regulated DNA methyltransferase (CcrM) methylates the adenine of hemimethylated GANTC after replication. Here we present the structure of CcrM in complex with double-stranded DNA containing the recognition sequence. CcrM contains an N-terminal methyltransferase domain and a C-terminal nonspecific DNA-binding domain. CcrM is a dimer, with each monomer contacting primarily one DNA strand: the methyltransferase domain of one molecule binds the target strand, recognizes the target sequence, and catalyzes methyl transfer, while the C-terminal domain of the second molecule binds the non-target strand. The DNA contacts at the 5-base pair recognition site results in dramatic DNA distortions including bending, unwinding and base flipping. The two DNA strands are pulled apart, creating a bubble comprising four recognized base pairs. The five bases of the target strand are recognized meticulously by stacking contacts, van der Waals interactions and specific Watson-Crick polar hydrogen bonds to ensure high enzymatic specificity.

SUBMITTER: Horton JR

PROVIDER: S-EPMC6787082 | biostudies-literature | 2019 Oct

REPOSITORIES: biostudies-literature

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The cell cycle-regulated DNA adenine methyltransferase CcrM opens a bubble at its DNA recognition site.

Horton John R JR Woodcock Clayton B CB Opot Sifa B SB Reich Norbert O NO Zhang Xing X Cheng Xiaodong X

Nature communications 20191010 1

The Caulobacter crescentus cell cycle-regulated DNA methyltransferase (CcrM) methylates the adenine of hemimethylated GANTC after replication. Here we present the structure of CcrM in complex with double-stranded DNA containing the recognition sequence. CcrM contains an N-terminal methyltransferase domain and a C-terminal nonspecific DNA-binding domain. CcrM is a dimer, with each monomer contacting primarily one DNA strand: the methyltransferase domain of one molecule binds the target strand, re ...[more]

PMID: 31601797

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The cell cycle-regulated DNA adenine methyltransferase CcrM opens a bubble at its DNA recognition site.

Publications

The cell cycle-regulated DNA adenine methyltransferase CcrM opens a bubble at its DNA recognition site.

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