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PDBsum entry 4y6c
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Unknown function
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PDB id
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4y6c
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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 naturally occurring repeat protein with high internal sequence identity defines a new class of tpr-Like proteins.
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Authors
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J.D.Marold,
J.M.Kavran,
G.D.Bowman,
D.Barrick.
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Ref.
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Structure, 2015,
23,
2055-2065.
[DOI no: ]
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PubMed id
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Abstract
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Linear repeat proteins often have high structural similarity and low (∼25%)
pairwise sequence identities (PSI) among modules. We identified a unique
P. anserina (Pa) sequence with tetratricopeptide repeat (TPR) homology, which
contains longer (42 residue) repeats (42PRs) with an average PSI >91%. We
determined the crystal structure of five tandem Pa 42PRs to 1.6 Å, and
examined the stability and solution properties of constructs containing three to
six Pa 42PRs. Compared with 34-residue TPRs (34PRs), Pa 42PRs have a one-turn
extension of each helix, and bury more surface area. Unfolding transitions shift
to higher denaturant concentration and become sharper as repeats are added.
Fitted Ising models show Pa 42PRs to be more cooperative than consensus 34PRs,
with increased magnitudes of intrinsic and interfacial free energies. These
results demonstrate the tolerance of the TPR motif to length variation, and
provide a basis to understand the effects of helix length on
intrinsic/interfacial stability.
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