Crystal structure and function of human nucleoplasmin (npm2): a histone chaperone in oocytes and embryos.
| Autor: | Platonova O; Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany St., Boston, Massachusetts 02118-2526, USA., Akey IV, Head JF, Akey CW |
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| Jazyk: | angličtina |
| Zdroj: | Biochemistry [Biochemistry] 2011 Sep 20; Vol. 50 (37), pp. 8078-89. Date of Electronic Publication: 2011 Aug 24. |
| DOI: | 10.1021/bi2006652 |
| Abstrakt: | 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. (© 2011 American Chemical Society) |
| Databáze: | MEDLINE |
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