1hue
From Proteopedia
HISTONE-LIKE PROTEIN
Structural highlights
FunctionDBH_GEOSE Histone-like DNA-binding protein which is capable of wrapping DNA to stabilize it, and thus to prevent its denaturation under extreme environmental conditions. Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe histone-like protein HU from Bacillus stearothermophilus is a dimer with a molecular mass of 19.5 kDa that is capable of bending DNA. An X-ray structure has been determined, but no structure could be established for a large part of the supposed DNA-binding beta-arms. Using distance and dihedral constraints derived from triple-resonance NMR data of a 13C/15N doubly-labelled HU protein 49 distance geometry structures were calculated, which were refined by means of restrained Molecular Dynamics. From this set a total of 25 refined structures were selected having low constraint energy and few constraint violations. The ensemble of 25 structures display a root-mea-square co-ordinate deviation of 0.36 A with respect to the average structure, calculated over the backbone heavy atoms of residues 2 to 54 and 75 to 90 (and residues 2' to 54' and 75' to 90' of the second monomer). The structure of the core is very similar to that observed in the X-ray structure, with a pairwise r.m.s.d. of 1.06 A. The structure of the beta-hairpin arm contains a double flip-over at the prolines in the two strands of the beta-arm. Strong 15N-NH heteronuclear nuclear Overhauser effects indicate that the beta-arm and especially the tip is flexible. This explains the disorder observed in the solution and X-ray structures of the beta-arm, in respect of the core of the protein. Overlayed onto itself the beta-arm is better defined, with an r.m.s.d. of 1.0 A calculated over the backbone heavy atoms of residues 54 to 59 and 69 to 74. The tip of the arm adopts a well-defined 4:6 beta-hairpin conformation similar to the iron co-ordinating beta-arms of rubredoxin. Solution structure of the HU protein from Bacillus stearothermophilus.,Vis H, Mariani M, Vorgias CE, Wilson KS, Kaptein R, Boelens R J Mol Biol. 1995 Dec 8;254(4):692-703. PMID:7500343[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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