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Spectroscopic Elucidation of Selected b‐Hairpin Turn Sequences
Author(s) -
Hardter Eric D.,
Rajagopal Karthikan,
Ramadan Danny,
Schneider Joel P.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a95-b
Subject(s) - turn (biochemistry) , computational biology , chemistry , biology , biochemistry
MAX 1 is a 20 amino acid β‐hairpin comprised of valine‐lysine repeats and a type II’ turn sequence of ‐V D PPT‐. This peptide undergoes triggered folding from random coil to β‐hairpin conformation. Subsequent self‐assembly of hairpins affords hydrogel material, which is currently being investigated for use in tissue engineering. Circular dichroism is used extensively to assess the secondary structure of these peptides during folding and self‐assembly. However, it is not known definitively how the turn sequence contributes to the spectroscopic data obtained. To elucidate this matter, a series of five 6‐residue turns (C‐V‐X‐X‐T‐C) has been synthesized, and subjected to circular dichroism, nuclear magnetic resonance, and infrared spectroscopic methods. Furthermore, all experiments were performed under oxidizing and reducing conditions, so as to mimic both folded and unfolded states through presence or absence of a disulfide bond. It is shown here that CD, IR and NMR spectra obtained not only differ amongst each turn, but also within each turn, showing a dependence on the disulfide bond. It can therefore be concluded that the conformation of each full‐length peptide in the MAX 1 family is contingent upon turn type. Funding: Howard Hughes Medical Institute