Optical reconstructions are intensity based. Xtallographic FT are amplitude based. The theoretical value for xray is about 0.9*dmin. Reading: Stenkamp, R.E. and L.H. Jensen. 1984 Resolution revisited. Acta Cryst., A40, 251-254. and the SFCHECK paper for other considerations Vaguine AA, Richelle J, & Wodak SJ (1999) SFCHECK: a unified set of procedures for evaluating the quality of macromolecular structure-factor data and their agreement with the atomic model. Acta Crystallogr. D55, 191-20.
BR -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of William Scott Sent: Thursday, May 15, 2008 10:56 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] poll: cutoff for "high resolution" Actually, if you want to feel really good, I learned (in the context of optics) that you can resolve two points separated by a distance x with a diffraction limit of x/0.7, so this means you can start to see carbon - carbon atomicity at 2.2 Å. On May 15, 2008, at 10:12 AM, Gloria Borgstahl wrote: > To me, it seems legal to use the words "atomic resolution" once we are > within the carbon-carbon bond length. So I'm agreeing with Dr. > Scott. > Otherwise I'll never get to use the words... > > ********************************************************************** > ******** > Gloria Borgstahl > Eppley Institute for Cancer Research and Allied Diseases > 987696 Nebraska Medical Center > 10732A Lied Transplant Center > Omaha, NE 68198-7696 > > http://sbl.unmc.edu > Office (402) 559-8578 > FAX (402) 559-3739 > > Associate Professor > Hobbies: Protein Crystallography, Cancer, Biochemistry, DNA > Metabolism, Modulated Crystals, Crystal Perfection, X-ray Topography, > Interests: ThimbleTack, skateboarding, RAGBRAI, and rollerskating > ********************************************************************** > ******** > > > > William Scott <[EMAIL PROTECTED]> Sent by: CCP4 bulletin > board <CCP4BB@JISCMAIL.AC.UK> > 05/15/2008 12:09 PM > Please respond to > William Scott <[EMAIL PROTECTED]> > > > To > CCP4BB@JISCMAIL.AC.UK > cc > > Subject > Re: [ccp4bb] poll: cutoff for "high resolution" > > > > > > > On May 15, 2008, at 10:01 AM, Ed Pozharski wrote: > >> 1.2A (not surprisingly since this is about the length of covalent >> bond). > > A carbon-carbon single bond is about 1.55 Å.
