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The consequences of cavity creation on the folding landscape of a repeat protein depend upon context

Cornell Affiliated Author(s)

Author

K.A. Jenkins
M.J. Fossat
S. Zhang
D.K. Rai
S. Klein
R. Gillilan
Z. White
G. Gerlich
S.A. McCallum
R. Winter
Sol Gruner
D. Barrick
C.A. Royer

Abstract

The effect of introducing internal cavities on protein native structure and global stability has been well documented, but the consequences of these packing defects on folding free-energy landscapes have received less attention. We investigated the effects of cavity creation on the folding landscape of the leucine-rich repeat protein pp32 by high-pressure (HP) and urea-dependent NMR and high-pressure small-angle X-ray scattering (HPSAXS). Despite a modest global energetic perturbation, cavity creation in the N-terminal capping motif (N-cap) resulted in very strong deviation from two-state unfolding behavior. In contrast, introduction of a cavity in the most stable, C-terminal half of pp32 led to highly concerted unfolding, presumably because the decrease in stability by the mutations attenuated the N- to C-terminal stability gradient present in WT pp32. Interestingly, enlarging the central cavity of the protein led to the population under pressure of a distinct intermediate in which the N-cap and repeats 1–4 were nearly completely unfolded, while the fifth repeat and the C-terminal capping motif remained fully folded. Thus, despite modest effects on global stability, introducing internal cavities can have starkly distinct repercussions on the conformational landscape of a protein, depending on their structural and energetic context. © National Academy of Sciences. All rights reserved.

Date Published

Journal

Proceedings of the National Academy of Sciences of the United States of America

Volume

115

Issue

35

Number of Pages

E8153-E8161,

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85053600907&doi=10.1073%2fpnas.1807379115&partnerID=40&md5=9ea34a5aad4f05e07ded65cd4699f134

DOI

10.1073/pnas.1807379115

Group (Lab)

Sol M. Gruner Group

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