X-ray diffraction in temporally and spatially resolved biomolecular science

Faraday Discuss. 2015:177:429-41. doi: 10.1039/c4fd00166d.

Abstract

Time-resolved Laue protein crystallography at the European Synchrotron Radiation Facility (ESRF) opened up the field of sub-nanosecond protein crystal structure analyses. There are a limited number of such time-resolved studies in the literature. Why is this? The X-ray laser now gives us femtosecond (fs) duration pulses, typically 10 fs up to ∼50 fs. Their use is attractive for the fastest time-resolved protein crystallography studies. It has been proposed that single molecules could even be studied with the advantage of being able to measure X-ray diffraction from a 'crystal lattice free' single molecule, with or without temporal resolved structural changes. This is altogether very challenging R&D. So as to assist this effort we have undertaken studies of metal clusters that bind to proteins, both 'fresh' and after repeated X-ray irradiation to assess their X-ray-photo-dynamics, namely Ta6Br12, K2PtI6 and K2PtBr6 bound to a test protein, hen egg white lysozyme. These metal complexes have the major advantage of being very recognisable shapes (pseudo spherical or octahedral) and thereby offer a start to (probably very difficult) single molecule electron density map interpretations, both static and dynamic. A further approach is to investigate the X-ray laser beam diffraction strength of a well scattering nano-cluster; an example from nature being the iron containing ferritin. Electron crystallography and single particle electron microscopy imaging offers alternatives to X-ray structural studies; our structural studies of crustacyanin, a 320 kDa protein carotenoid complex, can be extended either by electron based techniques or with the X-ray laser representing a fascinating range of options. General outlook remarks concerning X-ray, electron and neutron macromolecular crystallography as well as 'NMR crystallography' conclude the article.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bromides / chemistry*
  • Carotenoids / chemistry
  • Carrier Proteins / chemistry*
  • Crystallography, X-Ray
  • Electrons*
  • Ferritins / chemistry*
  • Lasers, Excimer
  • Light
  • Microscopy, Electron
  • Muramidase / chemistry*
  • Platinum Compounds / chemistry*
  • Synchrotrons
  • Tantalum / chemistry*
  • Time Factors
  • X-Ray Diffraction

Substances

  • Bromides
  • Carrier Proteins
  • Platinum Compounds
  • crustacyanins
  • tantalum bromide
  • Carotenoids
  • Tantalum
  • Ferritins
  • hen egg lysozyme
  • Muramidase