Dear bb, we actually solved quite a lot of structure with S-SAD on in-house systems with Cu radiation. Of course it is very difficult to give absolute numbers in term of S atoms per number of residues since the success of a SAD experiment strongly depends on the quality of the crystal and the point symmetry of the protein. As pointed out already by other people high multiplicity is essential. That requires a multiaxis (3circle or kappa) goniometer, a good strategy program as well as a very stable beam (in order to be able to appreciate small anomalous differences) and accuracy during data collection (narrow slicing frames). Here a list of some of the structures that were solved by S-SAD using in-house Cu source: insulin, thaumatin, glucoseisomerase, SOXB (2wdc.pdb), Human adenylate kinase.... And I am sure there are more around the world!!!
Marianna ---------------------------------------------------------------------------- Dr. Marianna Biadene Application Scientist Biological Crystallography Bruker AXS GmbH Oestliche Rheinbrueckenstrasse 49 76187 Karlsruhe, Germany Hotline: Phone XRD: +49 (721) 595-6288 Phone XRF: +49 (721) 595-2011 serv...@bruker-axs.de www.bruker-axs.com ---------------------------------------------------------------------------- -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Quyen Hoang Sent: Mittwoch, 11. November 2009 16:48 To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] sulfur sad phasing I played around with a few years back - tried all kinds of different data collection strategies and wavelengths. What worked for me was collecting data at wavelength of 1.7A from a few different crystals and then merge them together to get a higher redundancy. Both calcium and sulfur signals were visible and provided enough phasing power. Bone recognition mechanism of porcine osteocalcin from crystal structure. Hoang QQ, Sicheri F, Howard AJ, Yang DS. Nature. 2003 Oct 30;425(6961):977-80. Radiation damage was a concern with longer wavelength. Cheers, Quyen _______________________________ Quyen Hoang, Ph.D Department of Biochemistry and Molecular Biology, Start Neurosciences Research Institute Indiana University School of Medicine 635 Barnhill Drive, Room MS0013D Indianapolis, Indiana 46202-5122 Phone: 317-274-4371 Fax: 317-274-4686 email: qqho...@iupui.edu On Nov 11, 2009, at 10:23 AM, Jim Pflugrath wrote: > 2.29 Angstrom is an excellent wavelength for Cl, Ca and S anomalous > scatterers. This is the wavelength produced by a Cr home source. > Some older references: > > Acta Crystallogr D Biol Crystallogr. 2003 Nov;59(Pt 11):1943-57. > Epub 2003 > Oct 23. Away from the edge: SAD phasing from the sulfur anomalous > signal > measured in-house with chromium radiation. > > Acta Crystallogr D Biol Crystallogr. 2005 Jul;61(Pt 7):960-6. Epub > 2005 Jun > 24. Away from the edge II: in-house Se-SAS phasing with chromium > radiation. > > Acta Crystallogr D Biol Crystallogr. 2005 Aug;61(Pt 8):1013-21. Epub > 2005 > Jul 20. Structure determination of a novel protein by sulfur SAD using > chromium radiation in combination with a new crystal-mounting method. > > I'm sure there are several structures done with Cr radiation since > the above > articles were published. Does any body else want to chime in? > > Jim > > -----Original Message----- > From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of > Matthias Zebisch > Sent: Wednesday, November 11, 2009 6:16 AM > To: CCP4BB@JISCMAIL.AC.UK > Subject: [ccp4bb] sulfur sad phasing > > Dear bb! > > What is the optimal wavelength for Sulfur SAD phasing? > Is it 1.9A or should one go below that to reduce absorption/damage. > > Also, would the same wavelength be appropriate to maximize anomalous > scattering to position chlorides, calcium, sulfate in already phased > structures? > > Thanks in advance, > > Matthias ------------------------------------------------------------------------------------ Bruker AXS GmbH, Karlsruhe HRB 107524 Amtsgericht Mannheim, Umsatzsteuer-Ident.Nr. DE812037551, Geschäftsführer - Dr. Frank Burgäzy, Bernard Kolodziej, Stephan Franz Westermann ------------------------------------------------------------------------------------ Der Inhalt dieser E-Mail ist vertraulich und ausschliesslich fuer den bezeichneten Adressaten bestimmt. Wenn Sie nicht der vorgesehene Adressat dieser E-Mail oder dessen Vertreter sein sollten, so beachten Sie bitte, dass jede Form der Kenntnisnahme, Veroeffentlichung, Vervielfaeltigung oder Weitergabe des Inhalts dieser E-Mail unzulaessig ist. Wir bitten Sie, sich in diesem Fall mit dem Absender der E-Mail in Verbindung zu setzen. The information contained in this email is confidential. It is intended solely for the addressee. Access to this email by anyone else is unauthorized. If you are not the intended recipient, any form of disclosure, reproduction, distribution or any action taken or refrained from in reliance on it, is prohibited and may be unlawful. Please notify the sender immediately. ------------------------------------------------------------------------------------
