Crystal and NMR structures of a Trp-cage mini-protein benchmark for computational fold prediction

By Michele Scian, Jasper C. Lin, Isolde Le Trong, George I. Makhatadze, Ronald E. Stenkamp, Niels H. Andersen

July 28, 2017

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Title

Crystal and NMR structures of a Trp-cage mini-protein benchmark for computational fold prediction

Author

Michele Scian, Jasper C. Lin, Isolde Le Trong, George I. Makhatadze, Ronald E. Stenkamp, Niels H. Andersen

Year

2012

Journal

PNAS

Abstract

To provide high-resolution X-ray crystallographic structures of a peptide with the Trp-cage fold, we prepared a cyclized version of this motif. Cyclized Trp-cage is remarkably stable and afforded two crystal forms suitable for X-ray diffraction. The resulting higher resolution crystal structures validate the prior NMR models and provide explanations for experimental observations that could not be rationalized by NMR structural data, including the structural basis for the increase in fold stability associated with motif cyclization and the manner in which a polar serine side chain is accommodated in the hydrophobic interior. A hexameric oligomer of the cyclic peptide is found in both crystal forms and indicates that under appropriate conditions, this minimized system may also serve as a model for protein–protein interactions.

Full Article

http://www.pnas.org/content/109/31/12521.abstract

Instrument

J-720

Keywords

Circular dichroism, Secondary structure, Chemical stability, Thermal stability, Thermodynamics, Biochemistry