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Title
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Restored heptad pattern continuity does not alter the folding of a four-alpha-helix bundle.
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Authors
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M.Vlassi,
C.Steif,
P.Weber,
D.Tsernoglou,
K.S.Wilson,
H.J.Hinz,
M.Kokkinidis.
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Ref.
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Nat Struct Biol, 1994,
1,
706-716.
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PubMed id
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Abstract
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The sequences of alpha-helical coiled-coils and bundles are characterized by a
specific pattern of hydrophobic and hydrophilic residues which is repeated every
seven residues. Highly conserved breaks in this pattern frequently occur in
segments of otherwise continuous heptad substructures. The hairpin bend of the
ROP protein coincides with such a break and provides a model system for the
study of the structural effects induced by heptad discontinuities. The structure
of a ROP mutant which re-establishes a continuous heptad pattern, shows
insignificant changes relative to the wild-type protein, as is also reflected in
its conformational stability, spectroscopic properties and unfolding behaviour.
Thus, formation of alpha-alpha-hairpin bends may occur both in the presence and
absence of heptad breaks.
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