3T30

Human nucleoplasmin (Npm2): a histone chaperone in oocytes and early embryos

Summary for 3T30

• Entry DOI: 10.2210/pdb3t30/pdb
• Descriptor: Nucleoplasmin-2 (2 entities in total)
• Functional Keywords: beta-barrel jelly roll topology, histone chaperone, h2a-h2b dimer and h3-h4 tetramer, oocytes and early embryos, chaperone
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 10
• Total formula weight: 123944.25

Authors

Platonova, O.,Head, J.F.,Akey, C.W. (deposition date: 2011-07-23, release date: 2011-09-21, Last modification date: 2023-09-13)

Primary citation

Platonova, O.,Akey, I.V.,Head, J.F.,Akey, C.W.
Crystal structure and function of human nucleoplasmin (npm2): a histone chaperone in oocytes and embryos.
Biochemistry, 50:8078-8089, 2011

PubMed Abstract: Human Npm2 is an ortholog of Xenopus nucleoplasmin (Np), a chaperone that binds histones. We have determined the crystal structure of a truncated Npm2-core at 1.9 Å resolution and show that the N-terminal domains of Npm2 and Np form similar pentamers. This allowed us to model an Npm2 decamer which may be formed by hydrogen bonds between quasi-conserved residues in the interface between two pentamers. Interestingly, the Npm2 pentamer lacks a prototypical A1-acidic tract in each of its subunits. This feature may be responsible for the inability of Npm2-core to bind histones. However, Npm2 with a large acidic tract in its C-terminal tail (Npm2-A2) is able to bind histones and form large complexes. Fluorescence resonance energy transfer experiments and biochemical analysis of loop mutations support the premise that nucleoplasmins form decamers when they bind H2A-H2B dimers and H3-H4 tetramers simultaneously. In the absence of histone tetramers, these chaperones bind H2A-H2B dimers with a single pentamer forming the central hub. When taken together, our data provide insights into the mechanism of histone binding by nucleoplasmins.

PubMed: 21863821
DOI: 10.1021/bi2006652

Experimental method

X-RAY DIFFRACTION (1.9 Å)