3cb6
Crystal Structure of the S. pombe Peptidase Homology Domain of FACT complex subunit Spt16 (form B)
Structural highlights
FunctionSPT16_SCHPO Component of the FACT complex, a general chromatin factor that acts to reorganize nucleosomes. The FACT complex is involved in multiple processes that require DNA as a template such as mRNA elongation, DNA replication and DNA repair. During transcription elongation the FACT complex acts as a histone chaperone that both destabilizes and restores nucleosomal structure. It facilitates the passage of RNA polymerase II and transcription by promoting the dissociation of one histone H2A-H2B dimer from the nucleosome, then subsequently promotes the reestablishment of the nucleosome following the passage of RNA polymerase II (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe FACT complex is a conserved cofactor for RNA polymerase II elongation through nucleosomes. FACT bears histone chaperone activity and contributes to chromatin integrity. However, the molecular mechanisms behind FACT function remain elusive. Here we report biochemical, structural, and mutational analyses that identify the peptidase homology domain of the Schizosaccharomyces pombe FACT large subunit Spt16 (Spt16-N) as a binding module for histones H3 and H4. The 2.1-A crystal structure of Spt16-N reveals an aminopeptidase P fold whose enzymatic activity has been lost. Instead, the highly conserved fold directly binds histones H3-H4 through a tight interaction with their globular core domains, as well as with their N-terminal tails. Mutations within a conserved surface pocket in Spt16-N or posttranslational modification of the histone H4 tail reduce interaction in vitro, whereas the globular domains of H3-H4 and the H3 tail bind distinct Spt16-N surfaces. Our analysis suggests that the N-terminal domain of Spt16 may add to the known H2A-H2B chaperone activity of FACT by including a H3-H4 tail and H3-H4 core binding function mediated by the N terminus of Spt16. We suggest that these interactions may aid FACT-mediated nucleosome reorganization events. The FACT Spt16 "peptidase" domain is a histone H3-H4 binding module.,Stuwe T, Hothorn M, Lejeune E, Rybin V, Bortfeld M, Scheffzek K, Ladurner AG Proc Natl Acad Sci U S A. 2008 Jul 1;105(26):8884-9. Epub 2008 Jun 25. PMID:18579787[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||
