6m3h

From Proteopedia

Crystal structure of mouse HPF1

Structural highlights

6m3h is a 1 chain structure with sequence from Mus musculus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.71Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

HPF1_MOUSE Cofactor for serine ADP-ribosylation that confers serine specificity on PARP1 and PARP2 and plays a key role in DNA damage response. Initiates the repair of double-strand DNA breaks: recruited to DNA damage sites by PARP1 and PARP2 and switches the amino acid specificity of PARP1 and PARP2 from aspartate or glutamate to serine residues, licensing serine ADP-ribosylation of target proteins. Serine ADP-ribosylation of target proteins, such as histones, promotes decompaction of chromatin and the recruitment of repair factors leading to the reparation of DNA strand breaks. Serine ADP-ribosylation of proteins constitutes the primary form of ADP-ribosylation of proteins in response to DNA damage. HPF1 acts by completing the active site of PARP1 and PARP2: forms a composite active site composed of residues from HPF1 and PARP1 or PARP2. While HPF1 promotes the initiation of serine ADP-ribosylation, it restricts the polymerase activity of PARP1 and PARP2 in order to limit the length of poly-ADP-ribose chains. HPF1 also promotes tyrosine ADP-ribosylation, probably by conferring tyrosine specificity on PARP1.[UniProtKB:Q9NWY4]

Publication Abstract from PubMed

Upon binding to DNA breaks, poly(ADP-ribose) polymerase 1 (PARP1) ADP-ribosylates itself and other factors to initiate DNA repair. Serine is the major residue for ADP-ribosylation upon DNA damage, which strictly depends on HPF1. Here, we report the crystal structures of human HPF1/PARP1-CAT DeltaHD complex at 1.98 A resolution, and mouse and human HPF1 at 1.71 A and 1.57 A resolution, respectively. Our structures and mutagenesis data confirm that the structural insights obtained in a recent HPF1/PARP2 study by Suskiewicz et al. apply to PARP1. Moreover, we quantitatively characterize the key residues necessary for HPF1/PARP1 binding. Our data show that through salt-bridging to Glu284/Asp286, Arg239 positions Glu284 to catalyze serine ADP-ribosylation, maintains the local conformation of HPF1 to limit PARP1 automodification, and facilitates HPF1/PARP1 binding by neutralizing the negative charge of Glu284. These findings, along with the high-resolution structural data, may facilitate drug discovery targeting PARP1.

HPF1 remodels the active site of PARP1 to enable the serine ADP-ribosylation of histones.,Sun FH, Zhao P, Zhang N, Kong LL, Wong CCL, Yun CH Nat Commun. 2021 Feb 15;12(1):1028. doi: 10.1038/s41467-021-21302-4. PMID:33589610^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Sun FH, Zhao P, Zhang N, Kong LL, Wong CCL, Yun CH. HPF1 remodels the active site of PARP1 to enable the serine ADP-ribosylation of histones. Nat Commun. 2021 Feb 15;12(1):1028. PMID:33589610 doi:10.1038/s41467-021-21302-4