Helix-coil theories: a comparative study for finite length polypeptides

At present, numerous polypeptides of known sequence and length are being synthesized by chemical or biosynthetic means. The observations of the helix-coil transition is one of the important methods of studying the factors which stabilize {alpha}-helices of short to moderate length in these molecules. As a result, the observation and interpretation of helix-coil transitions is likely to return to its prominence of 25 years ago, but with increased power because of the precise sequence information and the ability to observe the state of individual amino acid residues or peptide groups by nuclear magnetic resonance spectroscopy and hydrogen-exchange methods. In this paper we develop some of the details of the helix-coil model, which are likely to be useful in the interpretation of these more incisive experiments. 37 refs., 2 figs.