Dear Qing, Many structures have been solved that way. Make sure you try solvent modification (flattening / flipping) on your map. This is because SAD will give two equally-probably estimates for the phase. The initial, unmodified map will use the average of the two, but solve modification should be able to break the amibiguity. It sounds like you're new to crystallography - do you have a local advisor to get help from? Phoebe
===================================== Phoebe A. Rice Dept. of Biochemistry & Molecular Biology The University of Chicago phone 773 834 1723 http://bmb.bsd.uchicago.edu/Faculty_and_Research/01_Faculty/01_Faculty_Alphabetically.php?faculty_id=123 http://www.rsc.org/shop/books/2008/9780854042722.asp ---- Original message ---- >Date: Mon, 30 Aug 2010 20:32:26 +0200 >From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> (on behalf of Jane Bailey ><jbailey.x...@googlemail.com>) >Subject: [ccp4bb] About SAD phasing >To: CCP4BB@JISCMAIL.AC.UK > > Hi, All > > I would like to ask whether is it possible to > allocate the Se site and obtain the phase by just > using the SAD data set (no native dataset used)? > > Thanks, > Qing