Starting with the density (or specific volume) of water, you can obtain rho(water)=0.33 e-/A^3. It's a nifty little bit of arithmetic and dimensional analysis.
-MW Michael C. Wiener, Ph.D. Professor Department of Molecular Physiology and Biological Physics University of Virginia PO Box 800886 Charlottesville, VA 22908-0886 434-243-2731 434-982-1616 (FAX) On Wed, 5 Feb 2014 10:39:57 -0800 Joseph Noel <n...@salk.edu> wrote: >Dear All, > >Is there a way or program that is good at providing a solid estimate of F000 >using the standard mean protein electron density of 0.433 e/A**3 and a mean >solvent electron density calculated from the crystallization conditions? I am >wondering how the latter might affect F000 if the conditions are a bit >different then the values assumed in most programs. > >I am "assuming" from these two values I can calculate a pretty good estimate >of F000 using: > >F000 = mean_electron_density*Vcell(e-), where >mean_electron_density=fraction_protein*0.433 e/A**3 + >fraction_solvent*mean_solvent_electron_density(e/A**3). > >In short, how can one calculate the average solvent density instead of using >the value assumed in many programs of 0.35? I know that 4M ammonium sulphate >is 0.41 and pure water is 0.33 but not sure how these values are measured (or >calculated). > >Thanks! > >Joe >______________________________________________________________________________________ >Joseph P. Noel, Ph.D. >Arthur and Julie Woodrow Chair >Investigator, Howard Hughes Medical Institute >Professor, The Jack H. Skirball Center for Chemical Biology and Proteomics >The Salk Institute for Biological Studies >10010 North Torrey Pines Road >La Jolla, CA 92037 USA > >Phone: (858) 453-4100 extension 1442 >Cell: (858) 349-4700 >Fax: (858) 597-0855 >E-mail: n...@salk.edu > >Publications & Citations: http://scholar.google.com/citations?user=xiL1lscAAAAJ > >Homepage Salk: http://www.salk.edu/faculty/noel.html >Homepage HHMI: http://hhmi.org/research/investigators/noel.html >______________________________________________________________________________________ >
