2a2y
NMR Structue of Sso10b2 from Sulfolobus solfataricus
Structural highlights
FunctionALBA2_SACS2 Binds double-stranded DNA tightly but without sequence specificity. It is distributed uniformly and abundantly on the chromosome, suggesting a role in chromatin architecture. However, it does not significantly compact DNA. Binds rRNA and mRNA in vivo. May play a role in maintaining the structural and functional stability of RNA, and, perhaps, ribosomes (By similarity). 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 Sso10b (or Alba) family of proteins is a conserved group of archaeal and eukaryotic proteins which are thought to play a role in both chromatin organization and RNA metabolism. We describe here the solution structure and properties of Sso10b2 from Sulfolobus solfataricus. NMR data including residual dipolar couplings and (15)N relaxation data demonstrated that the protein adopts a beta(1)alpha(1)beta(2)alpha(2)beta(3)beta(4) topology with an IF-3-like fold. The protein dimerizes in solution at 30 degrees C via a hydrophobic surface defined by the C-terminal alpha(2)beta(3)beta(4) elements with a structure similar to one of the putative dimers indicated by previous crystal structures. DSC and circular dichroism data demonstrated an unusual two-state structural transition near the growth temperature which led to an increase in beta-sheet content without dissociation of the dimer. The cooperativity of the transition exceeded that of a dimer at pH 7, demonstrating the presence of higher order oligomers near the growth temperature at pH 7. Reverse titrations of Sso10b2 with nucleic acid showed that the protein binds single-stranded DNA (K(d) of 3 x 10(-)(7) M) with higher affinity than RNA (1.3 x 10(-)(6) M) or double-stranded DNA (1.5 x 10(-)(5) M) in 10 mM KH(2)PO(4) (pH 7.0, 20 degrees C). NMR chemical shift perturbation data indicated that single-stranded DNA and RNA binding occurred across the same dimer interface and encompassed a surface defined by the C-terminal ends of the beta(1), beta(2), and beta(3) strands of each monomer. Solution structure, stability, and nucleic acid binding of the hyperthermophile protein Sso10b2.,Biyani K, Kahsai MA, Clark AT, Armstrong TL, Edmondson SP, Shriver JW Biochemistry. 2005 Nov 1;44(43):14217-30. PMID:16245938[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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