6pbd
DNA N6-Adenine Methyltransferase CcrM In Complex with Double-Stranded DNA Oligonucleotide Containing Its Recognition Sequence GAATC
Structural highlights
FunctionCCRM_CAUVC A beta subtype methylase that recognizes the double-stranded sequence 5'-GANTC-3' and methylates non-modifed A-2 on the hemimethylated, post-replicative DNA (Probable) (PubMed:12654995) (By similarity). Opens a bubble in the DNA at the recognition site, allowing precise recognition of the sequence and ensuring enzyme specificity (PubMed:31601797). Functions only in the predivisional cell. Responsible for 5'-GANTC-3' methylation in the cell; methylation of hemimethylated sites generated after replication fork passage occurs late in the predivisional cell, near completion of chromosome replication but prior to cell division. Contributes to the accurate cell-cycle control of DNA replication and cellular morphology (By similarity).[UniProtKB:B8GZ33][1] [2] [3] Publication Abstract from PubMedThe 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. The cell cycle-regulated DNA adenine methyltransferase CcrM opens a bubble at its DNA recognition site.,Horton JR, Woodcock CB, Opot SB, Reich NO, Zhang X, Cheng X Nat Commun. 2019 Oct 10;10(1):4600. doi: 10.1038/s41467-019-12498-7. PMID:31601797[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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