1qkx
From Proteopedia
Alpha-spectrin Src Homology 3 domain, N47A mutant in the distal loop.
Structural highlights
FunctionSPTN1_CHICK Morphologically, spectrin-like proteins appear to be related to spectrin, showing a flexible rod-like structure. They can bind actin but seem to differ in their calmodulin-binding activity. In nonerythroid tissues, spectrins, in association with some other proteins, may play an important role in membrane organization. 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 PubMedResidue Asn47 at position L1 of a type II' beta-turn of the alpha-spectrin SH3 domain is located in a disallowed region of the Ramachandran plot (phi = 56 +/- 12, psi = -118 +/- 17). Therefore, it is expected that replacement of Asn47 by Gly should result in a considerable stabilization of the protein. Thermodynamic analysis of the N47G and N47A mutants shows that the change in free energy is small (approximately 0.7 kcal/mol; approximately 3 kJ/mol) and comparable to that found when mutating a Gly to Ala in a alpha-helix or beta-sheet. X-ray structural analysis of these mutants shows that the conformation of the beta-turn does not change upon mutation and, therefore, that there is no relaxation of the structure, nor is there any gain or loss of interactions that could explain the small energy change. Our results indicate that the energetic definition of II' region of the Ramachandran plot (phi = 60 +/- 30, psi = -115 +/- 15) should be revised for at least Ala and Asn in structure validation and protein design. Thermodynamic and structural characterization of Asn and Ala residues in the disallowed II' region of the Ramachandran plot.,Vega MC, Martinez JC, Serrano L Protein Sci. 2000 Dec;9(12):2322-8. PMID:11206053[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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