2af5
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2.5A X-ray Structure of Engineered OspA protein
OverviewOverview
Although the beta-rich self-assemblies are a major structural class for, polypeptides and the focus of intense research, little is known about, their atomic structures and dynamics due to their insoluble and, noncrystalline nature. We developed a protein engineering strategy that, captures a self-assembly segment in a water-soluble molecule. A predefined, number of self-assembling peptide units are linked, and the beta-sheet, ends are capped to prevent aggregation, which yields a mono-dispersed, soluble protein. We tested this strategy by using Borrelia outer surface, protein (OspA) whose single-layer beta-sheet located between two globular, domains consists of two beta-hairpin units and thus can be considered as a, prototype of self-assembly. We constructed self-assembly mimics of, different sizes and determined their atomic structures using x-ray, crystallography and NMR spectroscopy. Highly regular beta-sheet geometries, were maintained in these structures, and peptide units had a nearly, identical conformation, supporting the concept that a peptide in the, regular beta-geometry is primed for self-assembly. However, we found small, but significant differences in the relative orientation between adjacent, peptide units in terms of beta-sheet twist and bend, suggesting their, inherent flexibility. Modeling shows how this conformational diversity, when propagated over a large number of peptide units, can lead to a, substantial degree of nanoscale polymorphism of self-assemblies.
About this StructureAbout this Structure
2AF5 is a Single protein structure of sequence from Borrelia burgdorferi. Full crystallographic information is available from OCA.
ReferenceReference
Atomic structures of peptide self-assembly mimics., Makabe K, McElheny D, Tereshko V, Hilyard A, Gawlak G, Yan S, Koide A, Koide S, Proc Natl Acad Sci U S A. 2006 Nov 21;103(47):17753-8. Epub 2006 Nov 8. PMID:17093048
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