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Title
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The design, synthesis, and crystallization of an alpha-helical peptide.
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Authors
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D.Eisenberg,
W.Wilcox,
S.M.Eshita,
P.M.Pryciak,
S.P.Ho,
W.F.DeGrado.
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Ref.
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Proteins, 1986,
1,
16-22.
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PubMed id
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Abstract
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Twelve- and sixteen-residue peptides have been designed to form tetrameric
alpha-helical bundles. Both peptides are capable of folding into amphiphilic
alpha-helices, with leucyl residues along one face and glutamyl and lysyl
residues along the opposite face. Four such amphiphilic alpha-helices are
capable of forming a noncovalently bonded tetramer. Neighboring helices run in
antiparallel directions in the design, so that the complex has 222 symmetry. In
the designed tetramer, the leucyl side chains interdigitate in the center in a
hydrophobic interaction, and charged side chains are exposed to the solvent. The
designed 12-mer (ALPHA-1) has been synthesized, and it forms helical aggregates
in aqueous solution as judged by circular dichroic spectroscopy. It has also
been crystallized and characterized by x-ray diffraction. The crystal symmetry
is compatible with (but does not prove) the design. The design can be extended
to a four-alpha-helical bundle formed from a single polypeptide by adding three
peptide linkers.
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