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TWITCHIN IMMUNOGLOBULIN SUPERFAMILY DOMAIN (IGSF MODULE) (IG 18'), NMR, 30 STRUCTURES
Structural highlights
FunctionUNC22_CAEEL Regulator of muscle contraction and relaxation. Senses mechanical strain that occurs during muscle activity by unfolding in clearly resolvable steps at differing forces.[1] [2] 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 NMR solution structure of an immunoglobulin superfamily module of twitchin (Ig 18') has been determined and the kinetic and equilibrium folding behaviour characterised. Thirty molecular coordinates were calculated using a hybrid distance geometry-simulated annealing protocol based on 1207 distance and 48 dihedral restraints. The atomic rms distributions about the mean coordinate for the ensemble of structures is 0.55( +/- 0.09) A for backbone atoms and 1.10( +/- 0.08) A for all heavy atoms. The protein has a topology very similar to that of telokin and the titin Ig domains and thus it falls into the I set of the immunoglobulin superfamily. The close agreement between the predicted and observed structures of Ig 18' demonstrates clearly that the I set profile can be applied in the structure prediction of immunoglobulin-like domains of diverse modular proteins. Folding studies reveal that the protein has relatively low thermodynamic stability, deltaG(H2O)U-F = 4.0 kcal mol(-1) at physiological pH. Unfolding studies suggest that the protein has considerable kinetic stability, the half life of the unfolding is greater than 40 minutes in the absence of denaturant. Structure and stability of an immunoglobulin superfamily domain from twitchin, a muscle protein of the nematode Caenorhabditis elegans.,Fong S, Hamill SJ, Proctor M, Freund SM, Benian GM, Chothia C, Bycroft M, Clarke J J Mol Biol. 1996 Dec 6;264(3):624-39. PMID:8969309[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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