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PDBsum entry 4s1x
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Viral protein
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PDB id
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4s1x
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References listed in PDB file
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Key reference
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Title
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A switch from parallel to antiparallel strand orientation in a coiled-Coil X-Ray structure via two core hydrophobic mutations.
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Authors
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V.N.Malashkevich,
C.D.Higgins,
S.C.Almo,
J.R.Lai.
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Ref.
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Biopolymers, 2015,
104,
178-185.
[DOI no: ]
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PubMed id
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Abstract
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The coiled-coil is one of the most ubiquitous and well studied protein
structural motifs. Significant effort has been devoted to dissecting subtle
variations of the typical heptad repeat sequence pattern that can designate
larger topological features such as relative α-helical orientation and oligomer
size. Here we report the X-ray structure of a model coiled-coil peptide,
HA2-Del-L2seM, which forms an unanticipated core antiparallel dimer with
potential sites for discrete higher-order multimerization (trimer or tetramer).
In the X-ray structure, a third, partially-ordered α-helix is weakly associated
with the antiparallel dimer and analytical ultracentrifugation experiments
indicate the peptide forms a well-defined tetramer in solution. The
HA2-Del-L2seM sequence is closely related to a parent model peptide, HA2-Del,
which we previously reported adopts a parallel trimer; HA2-Del-L2seM differs by
only hydrophobic leucine to selenomethione mutations and thus this subtle
difference is sufficient to switch both relative α-helical topology and number
of α-helices participating in the coiled-coil. Comparison of the X-ray
structures of HA2-Del-L2seM (reported here) with the HA2-Del parent (reported
previously) reveals novel interactions involving the selenomethionine residues
that promote antiparallel coiled-coil configuration and preclude parallel trimer
formation. These novel atomic insights are instructive for understanding subtle
features that can affect coiled-coil topology and provide additional information
for design of antiparallel coiled-coils. © 2015 Wiley Periodicals, Inc.
Biopolymers (Pept Sci) 104: 178-185, 2015.
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