4zcf | pdb_00004zcf

Structural basis of asymmetric DNA methylation and ATP-triggered long-range diffusion by EcoP15I

spinqualitylabelsall models 4zcf, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4zcf is a 5 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AMP, CA, MN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function T3RE_ECOLX A type III restriction enzyme that recognizes 2 inversely oriented double-stranded sequences 5'-CAGCAG-3' and cleaves DNA 25-27 base pairs downstream of one site. DNA restriction requires both the Res and Mod subunits (PubMed:11178902, PubMed:15464603). DNA topology affects its action; relaxed and negatively supercoiled DNA are digested but positively supercoiled DNA is not a good substrate (PubMed:11178902). Interacts with DNA approximately one half-turn downstream of the recognition site (PubMed:26067164). After binding to one recognition site undergoes random one-dimensional diffusion along DNA until it collides with a stationary enzyme bound to the second DNA site, which is when DNA cleavage occurs (Probable). Publication Abstract from PubMed Type III R-M enzymes were identified >40 years ago and yet there is no structural information on these multisubunit enzymes. Here we report the structure of a Type III R-M system, consisting of the entire EcoP15I complex (Mod2Res1) bound to DNA. The structure suggests how ATP hydrolysis is coupled to long-range diffusion of a helicase on DNA, and how a dimeric methyltransferase functions to methylate only one of the two DNA strands. We show that the EcoP15I motor domains are specifically adapted to bind double-stranded DNA and to facilitate DNA sliding via a novel 'Pin' domain. We also uncover unexpected 'division of labour', where one Mod subunit recognizes DNA, while the other Mod subunit methylates the target adenine-a mechanism that may extend to adenine N6 RNA methylation in mammalian cells. Together the structure sheds new light on the mechanisms of both helicases and methyltransferases in DNA and RNA metabolism. Structural basis of asymmetric DNA methylation and ATP-triggered long-range diffusion by EcoP15I.,Gupta YK, Chan SH, Xu SY, Aggarwal AK Nat Commun. 2015 Jun 12;6:7363. doi: 10.1038/ncomms8363. PMID:26067164 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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