Abstract
Increasingly time resolved X-ray crystallography and solid state NMR have been employed to characterize dynamics. In the advent of X-ray free electron sources at Stanford (LCLS), and Hamburg (European XFEL) there is a strong push to extend time-resolved measurements. A persistent question for these techniques however, is how the crystal contact forces may strongly perturb these dynamics from those in vivo. While some theoretical studies have indicated that the crystal contact perturbation is minor[1], other calculations suggest it is significant[2]. Surprisingly there have been few studies to actually determine from the data what the effects are. Given the enormous effort currently underway for extending crystal phase dynamics measurements, it is imperative to determine how the crystal contact forces affect large scale motions necessary for function. Here we show how anisotropic optical measurements in the extreme infrared (10-100 cm-1) using the technique of Crystal Anisotropy Terahertz Microscopy (CATM) can quantify the effect [3], by measuring the perturbation of the global motions for a given symmetry group. Chicken egg white lysozyme (CEWL) is used as a benchmarking model. Calculations and measurements are performed for tetragonal and monoclinic symmetry groups, for which B-factor measurements indicate that there is a significant difference in the motional constraint arising from the crystal geometry.1. Hafner, J. and W.J. Zheng, Optimal modeling of atomic fluctuations in protein crystal structures for weak crystal contact interactions. Journal of Chemical Physics, 2010. 132(1).2. Hinsen, K., Analysis of domain motions by approximate normal mode calculations. Proteins: Structure, Function, and Genetics, 1998. 33(3): p. 417-429.3. Acbas, G., K.A. Niessen, E.H. Snell, and A.G. Markelz, Optical measurements of long-range protein vibrations. Nat Commun, 2014. 5.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.