Hello Dr. Palmer- There may be other representatives in the literature by now but the one study I know of that examines the usefulness and limitations of determining "cryo"-neutron structures is "The 15-K neutron structure of saccharide-free
concanavalin A", Blakeley et al. (2004), PNAS, 47(101):16405-16410. There's a brief section there on the practicality of cooling such large crystals. Mark is right of course in that the vast majority of neutron data sets have been collected at RT, simply because neutrons are "soft" probes and non-damaging to the crystal, so there's no real need for cryocooling. However, the reason the authors give in the PNAS paper for collecting the data at cryo temps (mind you, this is helium and not nitrogen) is to help identify more solvent molecules in the sugar binding site. It also decfeased the B-factors for most of the atoms, too. This is severely paraphrasing the paper but hopefully you can take a look and see if it helps. Best- Brad On Wed, Sep 21, 2011 at 5:52 AM, REX PALMER <[email protected]>wrote: > Re Neutron Data Collection: > 1. What are the limits to data set completeness imposed by a Laue > experiment versus those of monochromatic data collection? > 2. What problems are caused by flash freezing the larger protein crystals > used for neutron data collection which do not occur for X-ray data > collection ie because smaller crystals can be used. > Any help will be greatly appreciated. > > Rex Palmer > http://www.bbk.ac.uk/biology/our-staff/emeritus-staff > http://rexpalmer2010.homestead.com >
