1y9x
From Proteopedia
Solution structure of Archaeon DNA-binding protein ssh10b
Structural highlights
FunctionALBA1_SACSH Binds double-stranded DNA tightly but without sequence specificity. It is distributed uniformly and abundantly on the chromosome, suggesting a role in chromatin architecture. May be involved in DNA compaction. Binds rRNA and mRNA in vivo. May play a role in maintaining the structural and functional stability of RNA, and, perhaps, ribosomes. 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 hyperthermophilic Ssh10b from Sulfolobus shibatae is a member of the Sac10b family, which has been postulated to play a role in chromosomal organization in Archaea. Ssh10b is capable of significantly constraining negative DNA supercoils at elevated temperatures. In this study, the solution structure of the dimeric P62A mutant Ssh10b ([P62A]Ssh10b) was determined by multidimensional NMR spectroscopy. The backbone 15N dynamics, H/D exchange with and without the denaturant GdmSCN, and chemical and thermal denaturation experiments were performed to investigate the molecular basis of high thermostability of [P62A]Ssh10b. Data analysis has revealed an alpha/beta-hydrophobic core consisting of two alpha-helices and one beta-sheet which are stabilized by cooperative hydrophobic and hydrogen-bonding interactions. This stabilizing alpha/beta-hydrophobic core of [P62A]Ssh10b exhibiting highly restricted internal motions is composed of residues having highly protected amide protons which exchange with solvent mostly by means of a global unfolding process. The K40N mutation greatly destabilizes the mutant [P62A]Ssh10b because this mutation disturbs the packing of alpha-helix against the beta-sheet reducing the stability of the alpha/beta-hydrophobic core in the mutant protein. In comparison with homologous mesophilic and thermophilic proteins, it can be presumed that the stabilizing alpha/beta-hydrophobic core in the [P62A]Ssh10b structure greatly contributes to the high thermostability of the protein. A stabilizing alpha/beta-hydrophobic core greatly contributes to hyperthermostability of archaeal [P62A]Ssh10b.,Fang X, Cui Q, Tong Y, Feng Y, Shan L, Huang L, Wang J Biochemistry. 2008 Oct 28;47(43):11212-21. Epub 2008 Sep 27. PMID:18821773[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found References
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