The Histone Chaperone Vps75 Forms Multiple Oligomeric Assemblies Capable of Mediating Exchange between Histone H3-H4 Tetramers and Asf1-H3-H4 Complexes.
Vps75 is a histone chaperone that has been historically characterized as homodimer by X-ray crystallography. In this study, we present a crystal structure containing two related tetrameric forms of Vps75 within the crystal lattice. We show Vps75 associates with histones in multiple oligomers ...
Vps75 is a histone chaperone that has been historically characterized as homodimer by X-ray crystallography. In this study, we present a crystal structure containing two related tetrameric forms of Vps75 within the crystal lattice. We show Vps75 associates with histones in multiple oligomers. In the presence of equimolar H3-H4 and Vps75, the major species is a reconfigured Vps75 tetramer bound to a histone H3-H4 tetramer. However, in the presence of excess histones, a Vps75 dimer bound to a histone H3-H4 tetramer predominates. We show the Vps75-H3-H4 interaction is compatible with the histone chaperone Asf1 and deduce a structural model of the Vps75-Asf1-H3-H4 (VAH) co-chaperone complex using the Pulsed Electron-electron Double Resonance (PELDOR) technique and cross-linking MS/MS distance restraints. The model provides a molecular basis for the involvement of both Vps75 and Asf1 in Rtt109 catalysed histone H3 K9 acetylation. In the absence of Asf1 this model can be used to generate a complex consisting of a reconfigured Vps75 tetramer bound to a H3-H4 tetramer. This provides a structural explanation for many of the complexes detected biochemically and illustrates the ability of Vps75 to interact with dimeric or tetrameric H3-H4 using the same interaction surface.
Related Citations:
The Histone Chaperones Vps75 and Nap1 Form Ring-Like, Tetrameric Structures in Solution. Bowman, A., Hammond, C.M., Stirling, A., Ward, R., Shang, W., El-Mkami, H., Robinson, D.A., Svergun, D.I., Norman, D.G., Owen-Hughes, T. (2014) Nucleic Acids Res 42: 6038
Organizational Affiliation:
Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK t.a.owenhughes@dundee.ac.uk.
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