PDBsum entry: 1uss

DNA binding protein

PDB id: 1uss

Contents

Protein chain

88 a.a. *

* Residue conservation analysis

PDB id:

1uss

Name:

DNA binding protein

Title:

Yeast histone h1 globular domain ii, hho1p gii, solution nmr structures

Structure:

Histone h1. Chain: a. Fragment: globular domain ii, residues 171-258. Engineered: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Expressed in: escherichia coli. Expression_system_taxid: 469008.

NMR struc:

10 models

Authors:

T.Ali,P.Coles,T.J.Stevens,K.Stott,J.O.Thomas

Key ref:

T.Ali et al. (2004). Two homologous domains of similar structure but different stability in the yeast linker histone, Hho1p. J Mol Biol, 338, 139-148. PubMed id: 15050829 DOI: 10.1016/j.jmb.2004.02.046

Date:

30-Nov-03 Release date: 01-Apr-04

Protein chain

P53551  (H1_YEAST) -  Histone H1

Seq: 258 a.a.

Struc: 88 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: nucleus (2 terms)
• Biological process: nucleosome assembly (1 term)
• Biochemical function: DNA binding (1 term)

DOI no: 10.1016/j.jmb.2004.02.046

J Mol Biol 338:139-148 (2004)

PubMed id: 15050829

Two homologous domains of similar structure but different stability in the yeast linker histone, Hho1p.

T.Ali, P.Coles, T.J.Stevens, K.Stott, J.O.Thomas.

ABSTRACT

The 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.

Selected figure(s)

Figure 2.
Figure 2. ¹⁵N-HSQC spectra at 288 K showing the GI domain and the effect of the concentration of sodium phosphate on the GII domain. (a) GI in 100 mM sodium phosphate; (b) GII in 100 mM sodium phosphate; (c) GII in 250 mM sodium phosphate. An unfolded conformation of GII in (b) is revealed by the presence of many small peaks in the range 8.0-8.5 ¹H ppm that disappear in (c). GII requires a minimum of 250 mM sodium phosphate in order to attain a single, stably folded conformation.

Figure 5.
Figure 5. Ribbon diagrams of (a) the top and (b) the front aspects of the generated cores of the GI (residues 47-117) and GII (residues 181-251) backbones, constructed using MOLMOL.[39.]

The above figures are reprinted by permission from Elsevier: J Mol Biol (2004, 338, 139-148) copyright 2004.

Figures were selected by the author.

Author's comment

Abstract
The 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 Å for GI and 0.97 Å 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 Å, 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.