5o6d | pdb_00005o6d

Structure of ScPif1 in complex with polydT and ATPgS

spinqualitylabelsall models 5o6d, resolution 3.28Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5o6d is a 4 chain structure with sequence from Baker's yeast. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: AGS, MG Gene: PIF1, TST1, YML061C, YM9958.01C (Baker's yeast) Activity: DNA helicase, with EC number 3.6.4.12 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PIF1_YEAST] DNA-dependent ATPase and 5'-3' DNA helicase required for the maintenance of both mitochondrial and nuclear genome stability. Efficiently unwinds G-quadruplex (G4) DNA structures and forked RNA-DNA hybrids. Appears to move along DNA in single nucleotide or base pair steps, powered by hydrolysis of 1 molecule of ATP. Processes at an unwinding rate of about 75 bp/s. Resolves G4 structures, preventing replication pausing and double-strand breaks (DSBs) at G4 motifs. Involved in the maintenance of telomeric DNA. Inhibits telomere elongation, de novo telomere formation and telomere addition to DSBs via catalytic inhibition of telomerase. Reduces the processivity of telomerase by displacing active telomerase from DNA ends. Releases telomerase by unwinding the short telomerase RNA/telomeric DNA hybrid that is the intermediate in the telomerase reaction. Involved in the maintenance of ribosomal (rDNA). Required for efficient fork arrest at the replication fork barrier within rDNA. Involved in the maintenance of mitochondrial (mtDNA). Required to maintain mtDNA under conditions that introduce dsDNA breaks in mtDNA, either preventing or repairing dsDNA breaks. May inhibit replication progression to allow time for repair. May have a general role in chromosomal replication by affecting Okazaki fragment maturation. May have a role in conjunction with DNA2 helicase/nuclease in 5'-flap extension during Okazaki fragment processing.[HAMAP-Rule:MF_03176] Publication Abstract from PubMed The Saccharomyces cerevisiae Pif1 protein (ScPif1p) is the prototypical member of the Pif1 family of DNA helicases. ScPif1p is involved in the maintenance of mitochondrial, ribosomal and telomeric DNA and suppresses genome instability at G-quadruplex motifs. Here, we report the crystal structures of a truncated ScPif1p (ScPif1p237-780) in complex with different ssDNAs. Our results have revealed that a yeast-specific insertion domain protruding from the 2B domain folds as a bundle bearing an alpha-helix, alpha16. The alpha16 helix regulates the helicase activities of ScPif1p through interactions with the previously identified loop3. Furthermore, a biologically relevant dimeric structure has been identified, which can be further specifically stabilized by G-quadruplex DNA. Basing on structural analyses and mutational studies with DNA binding and unwinding assays, a potential G-quadruplex DNA binding site in ScPif1p monomers is suggested. Our results also show that ScPif1p uses the Q-motif to preferentially hydrolyze ATP, and a G-rich tract is preferentially recognized by more residues, consistent with previous biochemical observations. These findings provide a structural and mechanistic basis for understanding the multifunctional ScPif1p. Insights into the structural and mechanistic basis of multifunctional S. cerevisiae Pif1p helicase.,Lu KY, Chen WF, Rety S, Liu NN, Wu WQ, Dai YX, Li D, Ma HY, Dou SX, Xi XG Nucleic Acids Res. 2017 Nov 30. pii: 4675318. doi: 10.1093/nar/gkx1217. PMID:29202194 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Helicase

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