5ftb

Crystal structure of Pif1 helicase from Bacteroides in complex with AMPPNP

spinqualitylabelsall models 5ftb, resolution 1.38Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ftb is a 1 chain structure with sequence from Bacteroides sp. 3_1_23. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ANP, K, MG Related: 5ftc, 5ftd, 5fte, 5ftf Activity: DNA helicase, with EC number 3.6.4.12 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Pif1 helicases are ubiquitous members of the SF1B family and are essential for maintaining genome stability. It was speculated that Pif1-specific motifs may fold in specific structures, conferring distinct activities upon it. Here, we report the crystal structures of the Pif1 helicase from Bacteroides spp with and without adenosine triphosphate (ATP) analog/ssDNA. BsPif1 shares structural similarities with RecD2 and Dda helicases but has specific features in the 1B and 2B domains. The highly conserved Pif1 family specific sequence motif interacts with and constraints a putative pin-loop in domain 1B in a precise conformation. More importantly, we found that the 2B domain which contains a specific extended hairpin undergoes a significant rotation and/or movement upon ATP and DNA binding, which is absolutely required for DNA unwinding. We therefore propose a mechanism for DNA unwinding in which the 2B domain plays a predominant role. The fact that the conformational change regulates Pif1 activity may provide insight into the puzzling observation that Pif1 becomes highly processive during break-induced replication in association with Poldelta, while the isolated Pif1 has low processivity. Crystal structures of the BsPif1 helicase reveal that a major movement of the 2B SH3 domain is required for DNA unwinding.,Chen WF, Dai YX, Duan XL, Liu NN, Shi W, Li N, Li M, Dou SX, Dong YH, Rety S, Xi XG Nucleic Acids Res. 2016 Jan 24. pii: gkw033. PMID:26809678 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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