Dear Dr. Thomas It's not SAD/MAD data I have solved it using molrep only.
I will try alternate positions for met and see the density again. Thanx to all for valuable suggestions Ethayathulla On Fri, 13 Apr 2007 Thomas Edwards wrote : > >Dear Ethayathulla , > >did you solve the structure by SeMet MAD or some other way? >Sometimes you get strange densities around the ends of methionine side >chains (around the S/Se) when switching from SeMet data to native. > >Cheers >Ed > > >______________ >T.Edwards Ph.D. >Astbury Centre for Structural Molecular Biology >University of Leeds, Leeds, LS2 9JT >Telephone: 0113 343 3031 > > -----Original Message----- > From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On >Behalf Of Ethayathulla Abdulsamath > Sent: Fri 13 Apr 2007 10:51 > To: [EMAIL PROTECTED] > Subject: [ccp4bb] Unusual Difference Fourier near Methionines > > > > > Dear all > > I am doing one structure at 2.6A resolution where I found >unusual density near methionines. Actually three methionines come close >together nearby and I get difference even at 5sigma cutoff. I don't >understand nature of the density. The amino acid sequnce is same I mean >met by chemical sequncing so there is no change amino acid residues. I >am sending the snapshot of the difference fourier observed at >methionines. The crystal belong to R32 system with one molecule and >biological trimer. In snapshot two of the methionines are symmetry >related. > > Details of the data collection. > Data collected at synchrotron > > Overall Rsym = 6 % and I/sigma = 2.1. Completeness = 99% > > Can anyone suggestion what could be chemical nature for the >difference fourier. > > Thanks in advance > > Ethayathulla > > ################################################### > A.S.Ethayathulla,Ph.D. > Department of Biophysics > All India Institute of Medical Sciences > Ansari Nagar > New Delhi-110029 > India. > ################################################### > > > >Imagine ><http://adworks.rediff.com/cgi-bin/AdWorks/click.cgi/www.rediff.com/sign >ature-home.htm/[EMAIL PROTECTED]/1152735_1146939/1151973/1?PARTNER=3&OA >S_QUERY=null target=new> > ################################################### A.S.Ethayathulla,Ph.D. Department of Biophysics All India Institute of Medical Sciences Ansari Nagar New Delhi-110029 India. ###################################################
