The CCP4 program rwcontents includes the data from Carugo & Bordo, Acta Cryst D, 55, 479 (1999)
Headline figures are 1.0 waters per protein residue at 2.0A, and 1.6-1.7 waters per protein residue at 1.0A. They use mainly room temperature, but also some cryo structures. And, as Clemens said, you shouldn't use this as a target... Martyn On Thu, 2007-05-17 at 13:56 +0100, Clemens Vonrhein wrote: > Hi Mark, > > I attach a little plot based on a quick analysis of recent PDB entries > (between Jan 04 and Nov 06, only Xray). This shows the number of > waters (HOH residues) per ATOM record (i.e. mainly protein, > RNA/DNA). If you want the number of waters per amino-acid residue, you > could just multiply it by about 10? > > Converted into a VERY ROUGH 'rule of thumb': > > 2.5 Angstroem = 0.5 water per residues > 2.0 1.0 > 1.5 1.5 > 1.0 2.0 > > But note the large error bars (at higher resolution probably because I > ignored alternate conformations and partially occupied waters): so you > have to do your own decision also based on the data quality and maps > yourself, I guess. And: this is what deposited structures tell us - > it doesn't mean we have to follow this. > > Hope that helps > > Cheers > > Clemens > > On Thu, May 17, 2007 at 03:44:14AM -0400, mark michaels wrote: > > Hello everyone, > > > > I would like to ask for any information on reasonable, preferably > > quantitatively derived values for the approximate crystallographic > > H2O to residue ratio versus resolution for protein structures ? > > > > Any references or studies would be ideal, but rules of thumb > > would also help. If there are any studies with greater detail, > > such as per residue type, I'd appreciate learning of them also. > > > > I'd specifically like this for cryo conditions since that would > > influence the results and my analysis involves structures > > determined under cryo conditions. > > > > Thanks for any help. > > > > m > > > > _________________________________________________________________ > > Catch suspicious messages before you open them?with Windows Live Hotmail. > > http://imagine-windowslive.com/hotmail/?locale=en-us&ocid=TXT_TAGHM_migration_HM_mini_protection_0507 > > >
