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The structure and function of Xenopus NO38-core, a histone binding chaperone in the nucleolusThe structure and function of Xenopus NO38-core, a histone binding chaperone in the nucleolus
Structural highlights
FunctionNPM_XENLA Acts as a chaperonin for the core histones H3, H2B and H4. Associated with nucleolar ribonucleoprotein structures and bind single-stranded nucleic acids. It may function in the assembly and/or transport of ribosome. May stimulate endonuclease activity on apurinic/apyrimidinic (AP) double-stranded DNA. May inhibit endonuclease activity on AP single-stranded RNA (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 PubMedXenopus NO38 is an abundant nucleolar chaperone and a member of the nucleoplasmin (Np) family. Here, we report high-resolution crystal structures of the N-terminal domain of NO38, as a pentamer and a decamer. As expected, NO38 shares the Np family fold. In addition, NO38- and Np-core pentamers each use highly conserved residues and numerous waters to form their respective decamers. Further studies show that NO38 and Np each bind equal amounts of the four core histones. However, NO38 prefers the (H3-H4)(2) tetramer, while Np probably prefers H2A-H2B dimers. We also show that NO38 and Np will each bind noncognate histones when the preferred partner is absent. We suggest that these chaperones must form decamers in order to bind histones and differentiate between histone tetramers and dimers. When taken together, these data imply that NO38 may function as a histone chaperone in the nucleolus. The structure and function of Xenopus NO38-core, a histone chaperone in the nucleolus.,Namboodiri VM, Akey IV, Schmidt-Zachmann MS, Head JF, Akey CW Structure. 2004 Dec;12(12):2149-60. PMID:15576029[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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