Helix Stop Signals in Proteins and Peptides: The Capping Box

Edwin T. Harper, George D. Rose

Research output: Contribution to journalArticlepeer-review

325 Scopus citations


The α-helix [Pauling, L., Corey, R. B., & Branson, H. R. (1951) Proc. Natl. Acad. Sci. U.S.A. 37, 205–211] is a common motif in both proteins and peptides. Despite intense investigation, predictive understanding of helices is still lacking. A recent hypothesis [Presta, L. G., & Rose, G. D. (1988) Science 240, 1632–1641] proposed that the structural specificity of helices resides, in part, in those residues that flank helix termini. If so, then signals that arrest helix propagation—i.e., helix stop signals—should be found among these flanking residues. Evidence is presented for the existence of one such signal, a reciprocal backbone-side-chain hydrogen-bonding interaction, dubbed the capping box. In proteins, the capping box is found uniquely at helix N-termini. In peptides, the capping box can function as a helix stop signal, as shown in the work of Kallenbach and co-workers.

Original languageEnglish (US)
Pages (from-to)7605-7609
Number of pages5
Issue number30
StatePublished - Aug 3 1993
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry


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