X-rays-Induced Cooperative Atomic Movement in a Protein Crystal

Insights into the mechanism of X-ray-induced disulfide-bond cleavage in lysozyme crystals based on EPR, optical absorption and X-ray diffraction studies

“…In addition, our model predicts that the initial reduction of disulfide bridges would not result in the scission of the bond. The disulfide scission observed by Petrova et al (2010) is likely to be owing to two one-electron reduction events at the disulfide bonds of elastase. Unlike the elastase study, in lysozyme no large-scale rigid-body structural changes or significant elongation of disulfide bonds are observed.…”

“…Other studies of disulfide damage have shown disulfide scission, in particular that of Petrova et al (2010) on elastase, which spanned doses of 1.2-30 MGy. We differ from Petrova and coworkers in the interpretation of the processes underlying their observations, but only in terms of the development of our multi-track model, which was not yet available at the time of the elastase study.…”

Neutron protein crystallography at ultra-low (<15 K) temperatures

“…atomic displacement parameters), better visualization of the more mobile parts of the system, freeze-trapping of unstable species (Bourgeois & Royant, 2005) and, when X-ray data can be extended to atomic resolutions (beyond 1.2 Å ), visualization of ordered H atoms in electron-density maps. Further reductions in dynamic disorder can be achieved by collecting data at temperatures down to 15 K (Petrova et al, 2006). A complication is that protein crystals typically contain 35-70% aqueous solvent and the cooling regimes in cryocrystallography must be sufficiently rapid (50À500 K s À1 ) to avoid ice formation that would otherwise disorder or destroy the sample (Teng & Moffat, 1998).…”

Contributions of charge-density research to medicinal chemistry

“…One topic of interest shared by CD studies and protein crystallography is the experiment because both require the best attainable data to give the most reliable answer to a particular structural problem. Here both research areas, CD (Coppens et al, 1974;Larsen, 1995;Stalke, 1998;Hardie et al, 1998) and macromolecular crystallography (Hope, 1990;Garman, 1999;Petrova et al, 2006;Chinte et al, 2007) usually rely on the use of low-temperature data collection and synchrotron radiation (Coppens, 1992;Helliwell, 1998); for example, when trying to identify the protonation state of a residue (Dauter et al, 1997), when collecting multiple anomalous dispersion data for solving the phase problem (Dauter et al, 1998), or when data devoid of strong bias from extinction and absorption of metal containing coordination complexes are collected to the highest possible resolution with hard X-rays (Schmö kel et al, 2013).…”