Helical hairpin structure of influenza hemagglutinin fusion peptide stabilized by charge-dipole interactions between the N-terminal amino group and the second helix.

ABSTRACT: The fusion domain of the influenza coat protein hemagglutinin HA2, bound to dodecyl phosphocholine micelles, was recently shown to adopt a structure consisting of two antiparallel α-helices, packed in an exceptionally tight hairpin configuration. Four interhelical H(α) to C═O aliphatic H-bonds were identified as factors stabilizing this fold. Here, we report evidence for an additional stabilizing force: a strong charge-dipole interaction between the N-terminal Gly(1) amino group and the dipole moment of helix 2. pH titration of the amino-terminal (15)N resonance, using a methylene-TROSY-based 3D NMR experiment, and observation of Gly(1 13)C' show a strongly elevated pK = 8.8, considerably higher than expected for an N-terminal amino group in a lipophilic environment. Chemical shifts of thr

SUBMITTER: Lorieau JL 

PROVIDER: S-EPMC3048900 | biostudies-literature | 2011 Mar

REPOSITORIES: biostudies-literature