a-Helix formation by peptides of defined sequence

The factors controlling a-helix formation in water by peptides of defined sequence are beginning to be understood. The field is close to the point where the extent of helix formation can be predicted for peptides of any sequence. Our own approach to the problem, and the main results obtained by following this approach, are summarized below. The chief reason for studying a-helix formation by peptides is to understand precisely and in detail one part of the protein folding problem. Questions about peptide helix formation can be answered at a fundamental level, in terms of the physico-chemical mechanisms involved. Key~~~rrk: Helix-stabilizing interaction; Helix propensity; N-cap 1. Early studies of helices formed by protein fragments The study of helix formation by peptide fragments of proteins began in 1971 with the report [I] by Brown and Klee that C-peptide (residues 1-13 of ribonuclease A, containing the N-terminal helix, residues 3-13) shows partial helix formation (abou