1RQW

Thaumatin Br soak: structure solution from either 2-wavelength MAD, or from single wavelength SAD

Prior to flash cooling in liquid nitrogen at 100 K the crystals were soaked for a few seconds in a solution containing 1 M sodium bromide and 25% (v/v) glycerol.

The peak and inflection datasets (360 images each) are available from the EMBL Hamburg website. The XDS data reductions are here.

Data reduction was performed starting with the template for the MarCCD 225 detector, changing

ORGX=1533 ORGY=1536
DETECTOR_DISTANCE=200
OSCILLATION_RANGE=0.5
X-RAY_WAVELENGTH=0.91878 ! peak
! X-RAY_WAVELENGTH=0.9196 ! inflection
NAME_TEMPLATE_OF_DATA_FRAMES=../peak/thau_peak_1_???.mccd DIRECT  TIFF
! NAME_TEMPLATE_OF_DATA_FRAMES=../inf/thau_inf_1_???.mccd DIRECT  TIFF
DATA_RANGE=1 360
SPACE_GROUP_NUMBER=92
UNIT_CELL_CONSTANTS= 57.8 57.8 150. 90 90 90
FRIEDEL'S_LAW=FALSE
VALUE_RANGE_FOR_TRUSTED_DETECTOR_PIXELS=9000. 30000.

SAD: Peak data alone

manual structure solution using hkl2map and buccaneer

The structure was solved using the hkl2map GUI. Based on

I decided to use 3.3 Å as a suitable cutoff for solving the substructure. SHELXD then found

and SHELXE produced useful phases:

automatic structure solution using Auto-Rickshaw

This uses Santosh Panjikar's script DPS2AR.csh:

DPS2AR.csh datafile1 thau-peak-I.mtz keeps world ver completeversion nres 207 nsm 20 masu 1 meth SAD SG P41212 \
           email kay.diederichs@uni-konstanz.de sequencefile 1rqw.seq

where 1rqw.seq is

ATFEIVNRCS YTVWAAASKG DAALDAGGRQ LNSGESWTIN VEPGTKGGKI WARTDCYFDD
SGSGICKTGD CGGLLRCKRF GRPPTTLAEF SLNQYGKDYI DISNIKGFNV PMDFSPTTRG
CRGVRCAADI VGQCPAKLKA PGGGCNDACT VFQTSEYCCT TGKCGPTEYS RFFKRLCPDA
FSYVLDKPTT VTCPGSSNYR VTFCPTA