Dataset Information

Solution structure and dynamics of the I214V mutant of the rabbit prion protein.

ABSTRACT: BACKGROUND: The conformational conversion of the host-derived cellular prion protein (PrP(C)) into the disease-associated scrapie isoform (PrP(Sc)) is responsible for the pathogenesis of transmissible spongiform encephalopathies (TSEs). Various single-point mutations in PrP(C)s could cause structural changes and thereby distinctly influence the conformational conversion. Elucidation of the differences between the wild-type rabbit PrP(C) (RaPrP(C)) and various mutants would be of great help to understand the ability of RaPrP(C) to be resistant to TSE agents. METHODOLOGY/PRINCIPAL FINDINGS: We determined the solution structure of the I214V mutant of RaPrP(C)(91-228) and detected the backbone dynamics of its structured C-terminal domain (121-228). The I214V mutant displays a visible shift of surface charge distribution that may have a potential effect on the binding specificity and affinity with other chaperones. The number of hydrogen bonds declines dramatically. Urea-induced transition experiments reveal an obvious decrease in the conformational stability. Furthermore, the NMR dynamics analysis discloses a significant increase in the backbone flexibility on the pico- to nanosecond time scale, indicative of lower energy barrier for structural rearrangement. CONCLUSIONS/SIGNIFICANCE: Our results suggest that both the surface charge distribution and the intrinsic backbone flexibility greatly contribute to species barriers for the transmission of TSEs, and thereby provide valuable hints for understanding the inability of the conformational conversion for RaPrP(C).

SUBMITTER: Wen Y

PROVIDER: S-EPMC2951349 | biostudies-literature | 2010

REPOSITORIES: biostudies-literature

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Solution structure and dynamics of the I214V mutant of the rabbit prion protein.

Wen Yi Y Li Jun J Xiong Minqian M Peng Yu Y Yao Wenming W Hong Jing J Lin Donghai D

PloS one 20101007 10

<h4>Background</h4>The conformational conversion of the host-derived cellular prion protein (PrP(C)) into the disease-associated scrapie isoform (PrP(Sc)) is responsible for the pathogenesis of transmissible spongiform encephalopathies (TSEs). Various single-point mutations in PrP(C)s could cause structural changes and thereby distinctly influence the conformational conversion. Elucidation of the differences between the wild-type rabbit PrP(C) (RaPrP(C)) and various mutants would be of great hel ...[more]

PMID: 20949107

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Project description:Prions are proteinaceous infectious agents responsible for fatal neurodegenerative diseases in animals and humans. They are essentially composed of PrP(Sc), an aggregated, misfolded conformer of the ubiquitously expressed host-encoded prion protein (PrP(C)). Stable variations in PrP(Sc) conformation are assumed to encode the phenotypically tangible prion strains diversity. However the direct contribution of PrP(Sc) quaternary structure to the strain biological information remains mostly unknown. Applying a sedimentation velocity fractionation technique to a panel of ovine prion strains, classified as fast and slow according to their incubation time in ovine PrP transgenic mice, has previously led to the observation that the relationship between prion infectivity and PrP(Sc) quaternary structure was not univocal. For the fast strains specifically, infectivity sedimented slowly and segregated from the bulk of proteinase-K resistant PrP(Sc). To carefully separate the respective contributions of size and density to this hydrodynamic behavior, we performed sedimentation at the equilibrium and varied the solubilization conditions. The density profile of prion infectivity and proteinase-K resistant PrP(Sc) tended to overlap whatever the strain, fast or slow, leaving only size as the main responsible factor for the specific velocity properties of the fast strain most infectious component. We further show that this velocity-isolable population of discrete assemblies perfectly resists limited proteolysis and that its templating activity, as assessed by protein misfolding cyclic amplification outcompetes by several orders of magnitude that of the bulk of larger size PrP(Sc) aggregates. Together, the tight correlation between small size, conversion efficiency and duration of disease establishes PrP(Sc) quaternary structure as a determining factor of prion replication dynamics. For certain strains, a subset of PrP assemblies appears to be the best template for prion replication. This has important implications for fundamental studies on prions.

Project description:The HIV-1 capsid protein plays a crucial role in viral infectivity, assembling into a cone that encloses the viral RNA. In the mature virion, the N-terminal domain of the capsid protein forms hexameric and pentameric rings, while C-terminal domain homodimers connect adjacent N-terminal domain rings to one another. Structures of disulfide-linked hexamer and pentamer assemblies, as well as structures of the isolated domains, have been solved previously. The dimer configuration in C-terminal domain constructs differs in solution (residues 144-231) and crystal (residues 146-231) structures by ∼30°, and it has been postulated that the former connects the hexamers while the latter links pentamers to hexamers. Here we study the structure and dynamics of full-length capsid protein in solution, comprising a mixture of monomeric and dimeric forms in dynamic equilibrium, using ensemble simulated annealing driven by experimental NMR residual dipolar couplings and X-ray scattering data. The complexity of the system necessitated the development of a novel computational framework that should be generally applicable to many other challenging systems that currently escape structural characterization by standard application of mainstream techniques of structural biology. We show that the orientation of the C-terminal domains in dimeric full-length capsid and isolated C-terminal domain constructs is the same in solution, and we obtain a quantitative description of the conformational space sampled by the N-terminal domain relative to the C-terminal domain on the nano- to millisecond time scale. The positional distribution of the N-terminal domain relative to the C-terminal domain is large and modulated by the oligomerization state of the C-terminal domain. We also show that a model of the hexamer/pentamer assembly can be readily generated with a single configuration of the C-terminal domain dimer, and that capsid assembly likely proceeds via conformational selection of sparsely populated configurations of the N-terminal domain within the capsid protein dimer.

Dataset Information

Solution structure and dynamics of the I214V mutant of the rabbit prion protein.

Publications

Solution structure and dynamics of the I214V mutant of the rabbit prion protein.

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