4c3g

cryo-EM structure of activated and oligomeric restriction endonuclease SgrAI

Loading... Status: waiting for Mol* initialization Structural highlights 4c3g is a 6 chain structure with sequence from Streptomyces griseus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 8.6Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9F6L0_STRGR Publication Abstract from PubMed SgrAI is a sequence specific DNA endonuclease that functions through an unusual enzymatic mechanism that is allosterically activated 200- to 500-fold by effector DNA, with a concomitant expansion of its DNA sequence specificity. Using single-particle transmission electron microscopy to reconstruct distinct populations of SgrAI oligomers, we show that in the presence of allosteric, activating DNA, the enzyme forms regular, repeating helical structures characterized by the addition of DNA-binding dimeric SgrAI subunits in a run-on manner. We also present the structure of oligomeric SgrAI at 8.6 A resolution, demonstrating the conformational state of SgrAI in its activated form. Activated and oligomeric SgrAI displays key protein-protein interactions near the helix axis between its N termini, as well as allosteric protein-DNA interactions that are required for enzymatic activation. The hybrid approach reveals an unusual mechanism of enzyme activation that explains SgrAI's oligomerization and allosteric behavior. Allosteric Regulation of DNA Cleavage and Sequence-Specificity through Run-On Oligomerization.,Lyumkis D, Talley H, Stewart A, Shah S, Park CK, Tama F, Potter CS, Carragher B, Horton NC Structure. 2013 Sep 17. pii: S0969-2126(13)00304-3. doi:, 10.1016/j.str.2013.08.012. PMID:24055317 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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