Structure and stability of an immunoglobulin superfamily domain from twitchin, a muscle protein of the nematode Caenorhabditis elegans.Fong, S., Hamill, S.J., Proctor, M., Freund, S.M., Benian, G.M., Chothia, C., Bycroft, M., Clarke, J.
(1996) J.Mol.Biol. 264: 624-639
- PubMed: 8969309
- DOI: 10.1006/jmbi.1996.0665
- Primary Citation of Related Structures:
- PubMed Abstract:
- Sequence of an Unusually Large Protein Implicated in Regulation of Myosin Activity in C. Elegans
Benian, G.M.,Kiff, J.E.,Neckelmann, N.,Moerman, D.G.,Waterston, R.H.
(1989) Nature 342: 45
- Additional Sequence Complexity in the Muscle Gene, Unc-22, and its Encoded Protein, Twitchin, of Caenorhabditis Elegans
Benian, G.M.,L'Hernault, S.W.,Morris, M.E.
(1993) Genetics 134: 1097
The 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 ...
The 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.
Centre for Protein Engineering, MRC Unit of Protein Folding and Design, Cambridge, UK.