>Packing billions of copies into a compact lattice Not so compact there is 40-80% water >freezing it to 100K We have frozen many times protein solutions in liquid nitrogen and then thaw and were working OK > non-physiological amounts of salt and various organics What is the amount of salt and osmotic pressure in the cell?? >non-physiological pH too What is the non-physiological pH too? I am sure that some enzymes they are not working in pH 7. Also most of the proteins they have crystallized in pH close to 7 so I would not say non-physiological.
George PS There are lots of solution NMR structures as well supporting the physiological crystal structures -----Original Message----- From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Nat Echols Sent: Friday, February 10, 2012 10:35 PM To: [email protected] Subject: Re: [ccp4bb] Crystal Structures as Snapshots On Fri, Feb 10, 2012 at 12:29 PM, James Stroud <[email protected]> wrote: > How could they not be snapshots of conformations adopted in solution? Packing billions of copies of an irregularly-shaped protein into a compact lattice and freezing it to 100K isn't necessarily representative of "solution", especially when your solution contains non-physiological amounts of salt and various organics (and possibly non-physiological pH too). -Nat
