*** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.ccp4.ac.uk ***
As we all know, the diffraction intensities do not have to be measured at an absorption edge to detect a useful anomalous signal: there is almost always anomalous scattering at any wavelength you choose. It's just a matter of measuring it. And a single wavelength often suffices. So one can do a SAD experiment within a broad range of wavelengths (for instance: 1.54 Angstrom) and phase on the signal from S, Cl, Ca, and other atoms. The literature is full of such instances. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Edward Berry Sent: Friday, November 10, 2006 4:56 PM To: Richard Gillilan Cc: CCP4 Subject: Re: [ccp4bb]: MAD at very low energy? *** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.ccp4.ac.uk *** Richard Gillilan wrote: > I know that some work has been done on phasing from Sulfur (2.47 keV). > Does anyone know of work on > phasing from P, Cl, Ar, K, or Ca? > > Are there any very important systems that might benefit from MAD in > range 2-5 keV? > P anomalous signal would be very useful for identifying phospholipids in membrane protein structures, and ATP and other nucleotides in enzymes - but I understand it is completely impractical? Ed
