The histone chaperone nucleosome assembly protein 1 (NAP1) is implicated in histone shuttling as well as nucleosome assembly and disassembly. Under physiological conditions, NAP1 dimers exist in a mixture of various high-molecular-weight oligomers whose size may be regulated by the cell cycle-dependent concentration of NAP1. Both the functional and structural significance of the observed oligomers are unknown. We have resolved the molecular mechanism by which yeast NAP1 (yNAP1) dimers oligomerize by applying x-ray crystallographic, hydrodynamic, and functional approaches. We found that an extended beta-hairpin that protrudes from the compact core of the yNAP1 dimer forms a stable beta-sheet with beta-hairpins of neighboring yNAP1 dimers. Disruption of the beta-hairpin (whose sequence is conserved among NAP1 proteins in various species) by the replacement of one or more amino acids with proline results in complete loss of yNAP1 dimer oligomerization. The in vitro functions of yNAP1 remain unaffected by the mutations. We have thus identified a conserved structural feature of NAP1 whose function, in addition to presenting the nuclear localization sequence, appears to be the formation of higher-order oligomers.
We have not found any resources mentioned in this publication.
SciCrunch® is a data sharing and display platform. Anyone can create a custom portal where they can select searchable subsets of hundreds of data sources, brand their web pages and create their community. SciCrunch® will push data updates automatically to all portals on a weekly basis. User communities can also add their own data to SciCrunch®, however this is not currently a free service.