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| - | [[Image:1b4o.jpg|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_1b4o| PDB=1b4o | SCENE= }} | | {{STRUCTURE_1b4o| PDB=1b4o | SCENE= }} |
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| - | '''NMR STUDY OF SSO7D MUTANT (F31A) MINIMIZED AVERAGE STRUCTURE'''
| + | ===NMR STUDY OF SSO7D MUTANT (F31A) MINIMIZED AVERAGE STRUCTURE=== |
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| - | ==Overview==
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| - | Sso7d is a basic 7-kDa DNA-binding protein from Sulfolobus solfataricus, also endowed with ribonuclease activity. The protein consists of a double-stranded antiparallel beta-sheet, onto which an orthogonal triple-stranded antiparallel beta-sheet is packed, and of a small helical stretch at the C-terminus. Furthermore, the two beta-sheets enclose an aromatic cluster displaying a fishbone geometry. We previously cloned the Sso7d-encoding gene, expressed it in Escherichia coli, and produced several single-point mutants, either of residues located in the hydrophobic core or of Trp23, which is exposed to the solvent and plays a major role in DNA binding. The mutation F31A was dramatically destabilizing, with a loss in thermo- and piezostabilities by at least 27 K and 10 kbar, respectively. Here, we report the solution structure of the F31A mutant, which was determined by NMR spectroscopy using 744 distance constraints obtained from analysis of multidimensional spectra in conjunction with simulated annealing protocols. The most remarkable finding is the change in orientation of the Trp23 side chain, which in the wild type is completely exposed to the solvent, whereas in the mutant is largely buried in the aromatic cluster. This prevents the formation of a cavity in the hydrophobic core of the mutant, which would arise in the absence of structural rearrangements. We found additional changes produced by the mutation, notably a strong distortion in the beta-sheets with loss in several hydrogen bonds, increased flexibility of some stretches of the backbone, and some local strains. On one hand, these features may justify the dramatic destabilization provoked by the mutation; on the other hand, they highlight the crucial role of the hydrophobic core in protein stability. To the best of our knowledge, no similar rearrangement has been so far described as a result of a single-point mutation.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_10504241}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 10504241 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_10504241}} |
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| | ==About this Structure== | | ==About this Structure== |
| - | 1B4O is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Sulfolobus_solfataricus Sulfolobus solfataricus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B4O OCA]. | + | 1B4O is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Sulfolobus_solfataricus Sulfolobus solfataricus]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B4O OCA]. |
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| | ==Reference== | | ==Reference== |
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| | [[Category: Sulfolobus solfataricus]] | | [[Category: Sulfolobus solfataricus]] |
| | [[Category: Thermostable ribonuclease]] | | [[Category: Thermostable ribonuclease]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:03:58 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 18:15:09 2008'' |
Revision as of 15:15, 30 June 2008
Template:STRUCTURE 1b4o
NMR STUDY OF SSO7D MUTANT (F31A) MINIMIZED AVERAGE STRUCTURE
Template:ABSTRACT PUBMED 10504241
About this Structure
1B4O is a Single protein structure of sequence from Sulfolobus solfataricus. Full experimental information is available from OCA.
Reference
A single-point mutation in the extreme heat- and pressure-resistant sso7d protein from sulfolobus solfataricus leads to a major rearrangement of the hydrophobic core., Consonni R, Santomo L, Fusi P, Tortora P, Zetta L, Biochemistry. 1999 Sep 28;38(39):12709-17. PMID:10504241
Page seeded by OCA on Mon Jun 30 18:15:09 2008
