| Popis: |
The conformation of the biologically-active tridecapeptide, neurotensin, has been predicted by a procedure including a continuum method for solvent effects on conformation. The neurotensin conformation is described as a β-type chain with breaks or “corners” most obvious at Tyr3, Asn5, Lys6, Arg8 and Tyr11. The general problem of predicting conformation of larger peptides is emphasized by comparison of the structures of neurotensin and its fragments obtained by other workers with the calculation carried out here on the entire molecule including the effects of the solvent-dependent reaction field. This inclusion of the reaction field leads to a further, equally-plausible conformation, which is more justifiable physically as well as in terms of the pharmacological data available on neurotensin. Factors leading to different residue conformations and the relative merits of the different results obtained are analyzed in some detail to cast further light on the aspects that must be considered in the analysis and design of biologically-active analogues of neurotensin. |
