2Z2R: Nucleosome Assembly Proteins I (Nap-1, 74-365)

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.
PDB ID: 2Z2RDownload
MMDB ID: 62951
PDB Deposition Date: 2007/5/25
Updated in MMDB: 2012/12
Experimental Method:
x-ray diffraction
Resolution: 3.2  Å
Source Organism:
Similar Structures:
Biological Unit for 2Z2R: dimeric; determined by author and by software (PISA,PQS)
Molecular Components in 2Z2R
Label Count Molecule
Proteins (2 molecules)
Nucleosome Assembly Protein(Gene symbol: NAP1)
Molecule annotation
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