Re: [ccp4bb] fixing position in the refinement: Shelx, refmac5

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

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Subject: Re: fixing position in the refinement: Shelx, refmac5
From: Frank von Delft frank {- dot -} vondelft {- at -} SGC {- dot -} OX {- dot -} AC {- dot -} UK
Date: 2008-04-04

Next message:
Subject: Re: fixing position in the refinement: Shelx, refmac5
From: Garib Murshudov garib {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2008-04-04

Subject: Re: fixing position in the refinement: Shelx, refmac5
From: "George M {- dot -} Sheldrick" gsheldr {- at -} SHELX {- dot -} UNI-AC {- dot -} GWDG {- dot -} DE
Date: 2008-04-04

For SHELX there are two ways to fix selected atoms: either put AFIX 1
in front of the fixed atoms and AFIX 0 after them, or use the BLOC
instruction. e.g.

BLOC 1 N_1 > C_53 N_57 > C61 N_62 CA_62 C_62 O_62 N_63 > LAST
BLOC -1 N_1 > C_53 N_57 > C61 N_62 CA_62 C_62 O_62 N_63 > LAST

would fix residues 54-56 and the side-chain of residue 62 (but you may
need to consider the order of atoms). This would be easier than using
AFIX if you are already using AFIX for riding hydrogens, however it is
OK to fix atoms with AFIX 1 and then use HFIX in the same job to add
hydrogens. I have deliberately chosen a complicated example to show how
easy it is!

More details on SHELXL refinements are now available from the CCP4 Wiki:
http://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/SHELXL

and for SHELXC, D and E see:
http://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/SHELX_C/D/E

Note that since this is a Wiki, users are encouraged to contribute!

George

Prof. George M. Sheldrick FRS
Dept. Structural Chemistry,
University of Goettingen,
Tammannstr. 4,
D37077 Goettingen, Germany
Tel. +49-551-39-3021 or -3068
Fax. +49-551-39-2582

On Thu, 3 Apr 2008, U Sam wrote:

> How one can fix position of few residues when refining in SHELX or Refmac5.
> Thanks. Sam.
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> Use video conversation to talk face-to-face with Windows Live Messenger.
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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Next message:
Subject: Re: fixing position in the refinement: Shelx, refmac5
From: Garib Murshudov garib {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2008-04-04