6L3G image
Entry Detail
PDB ID:
6L3G
Keywords:
HYDROLASE/DNA
Title:
Structural Basis for DNA Unwinding at Forked dsDNA by two coordinating Pif1 helicases
Biological Source:
Source Organism:
Bacteroides sp. AF32-8BH, Homo sapiens
Host Organism:
Escherichia coli BL21(DE3)
PDB Version:
Deposition Date:
2019-10-10
Release Date:
2019-12-11
Method Details:
Experimental Method:
X-RAY DIFFRACTION
Resolution:
3.30 Å
R-Value Free:
0.30
R-Value Work:
0.24
R-Value Observed:
0.24
Space Group:
P 31 1 2
6L3G validation report
Macromolecular Entities
Protein Blast
Polymer Type:polypeptide(L)
Description:ATP-dependent DNA helicase
Chain IDs:B (auth: A), C (auth: B)
Chain Length:433
Number of Molecules:2
Biological Source:Bacteroides sp. AF32-8BH
UniProt ID:A0A373G551 Pfam ID:PF05970
Polymer Type:polydeoxyribonucleotide
Description:DNA (5'-D(P*TP*TP*TP*TP*TP*TP*TP*CP*GP*CP*GP*CP*GP*CP*GP*CP*GP*TP*TP*TP*T)-3')
Chain IDs:A (auth: D)
Chain Length:30
Number of Molecules:1
Biological Source:Homo sapiens
Ligand Molecules
ADP
ALF
MG
Primary Citation
Structural basis for DNA unwinding at forked dsDNA by two coordinating Pif1 helicases.
Nat Commun 10 5375 5375 (2019)
PMID: 31772234 DOI: 10.1038/s41467-019-13414-9

Abstact

Pif1 plays multiple roles in maintaining genome stability and preferentially unwinds forked dsDNA, but the mechanism by which Pif1 unwinds forked dsDNA remains elusive. Here we report the structure of Bacteroides sp Pif1 (BaPif1) in complex with a symmetrical double forked dsDNA. Two interacting BaPif1 molecules are bound to each fork of the partially unwound dsDNA, and interact with the 5' arm and 3' ss/dsDNA respectively. Each of the two BaPif1 molecules is an active helicase and their interaction may regulate their helicase activities. The binding of BaPif1 to the 5' arm causes a sharp bend in the 5' ss/dsDNA junction, consequently breaking the first base-pair. BaPif1 bound to the 3' ss/dsDNA junction impacts duplex unwinding by stabilizing the unpaired first base-pair and engaging the second base-pair poised for breaking. Our results provide an unprecedented insight into how two BaPif1 coordinate with each other to unwind the forked dsDNA.

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Disease

Primary Citation of related structures
6L3G