1ust | pdb_00001ust
YEAST HISTONE H1 GLOBULAR DOMAIN I, HHO1P GI, SOLUTION NMR STRUCTURES
Structural highlights
Function[H1_YEAST] Could act as an H1-type linker histone. Has been shown to bind DNA.[1] [2] 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 PubMedThe Saccharomyces cerevisiae homologue of the linker histone H1, Hho1p, has two domains that are similar in sequence to the globular domain of H1 (and variants such as H5). It is an open question whether both domains are functional and whether they play similar structural roles. Preliminary structural studies showed that the two isolated domains, GI and GII, differ significantly in stability. In 10 mM sodium phosphate (pH 7), the GI domain, like the globular domains of H1 and H5, GH1 and GH5, was stably folded, whereas GII was largely unstructured. However, at high concentrations of large tetrahedral anions (phosphate, sulphate, perchlorate), which might mimic the charge-screening effects of DNA phosphate groups, GII was folded. In view of the potential significance of these observations in relation to the role of Hho1p, we have now determined the structures of its GI and GII domains by NMR spectroscopy under conditions in which GII (like GI) is folded. The backbone r.m.s.d. over the ordered residues is 0.43 A for GI and 0.97 A for GII. Both structures show the "winged-helix" fold typical of GH1 and GH5 and are very similar to each other, with an r.m.s.d. over the structured regions of 1.3 A, although there are distinct differences. The potential for GII to adopt a structure similar to that of GI when Hho1p is bound to chromatin in vivo suggests that both globular domains might be functional. Whether Hho1p performs a structural role by bridging two nucleosomes remains to be determined. Two homologous domains of similar structure but different stability in the yeast linker histone, Hho1p.,Ali T, Coles P, Stevens TJ, Stott K, Thomas JO J Mol Biol. 2004 Apr 16;338(1):139-48. PMID:15050829[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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