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

Autor:	Jenkins KA; Graduate Program in Biochemistry and Biophysics, Rensselaer Polytechnic Institute, Troy, NY 12180., Fossat MJ; Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180., Zhang S; Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180., Rai DK; Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853., Klein S; T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218., Gillilan R; Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853., White Z; Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180., Gerlich G; Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180., McCallum SA; Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180., Winter R; Department of Physical Chemistry, Technical University of Dortmund, 44227 Dortmund, Germany., Gruner SM; Cornell High Energy Synchrotron Source, Cornell University, Ithaca, NY 14853.; Department of Physics, Cornell University, Ithaca, NY 14853.; Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853., Barrick D; T. C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218., Royer CA; Graduate Program in Biochemistry and Biophysics, Rensselaer Polytechnic Institute, Troy, NY 12180; royerc@rpi.edu.; Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180.; Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2018 Aug 28; Vol. 115 (35), pp. E8153-E8161. Date of Electronic Publication: 2018 Aug 13.
DOI:	10.1073/pnas.1807379115
Abstrakt:	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. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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