5t1i

Publication Abstract from PubMed

Heterochromatin protein 1 (HP1), a highly conserved non-histone chromosomal protein in eukaryotes, plays important roles in the regulation of gene transcription. Each of the three human homologs of HP1 includes a chromoshadow domain (CSD). The CSD interacts with various proteins bearing the PxVxL motif, but also with a region of histone H3 that bears the similar PxxVxL motif. The latter interaction has not yet been resolved in atomic detail. Here we demonstrate that the CSDs of all three human HP1 homologs have comparable affinities to the PxxVxL motif of histone H3. The HP1 C-terminal extension (CTE) enhances the affinity, as does the increasing length of the H3 peptide. The crystal structure of the human HP1gamma CSD (CSDgamma) in complex with an H3 peptide suggests that recognition of H3 by CSDgamma to some extent resembles CSD-PxVxL interaction. Nevertheless, the prolyl residue (P) of the PxxVxL motif appears to play a distinct role from that of P in the known HP1beta CSD-PxVxL complexes. We consequently generalize the historical CSD-PxVxL interaction model and expand the search scope for additional CSD binding partners.

Peptide recognition by HP1 chromoshadow domains revisited: plasticity in the pseudosymmetric histone binding site of human HP1.,Liu Y, Qin S, Lei M, Tempel W, Zhang Y, Loppnau P, Li Y, Min J J Biol Chem. 2017 Feb 21. pii: jbc.M116.768374. doi: 10.1074/jbc.M116.768374. PMID:28223359^[1]

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