Correction of X-ray intensities from single crystals containing lattice-translocation defects.
In 1954, Howells and colleagues described an unusual diffraction pattern from imidazole methemoglobin crystals caused by lattice-translocation defects. In these crystals, two identical lattices coexist as a single coherent mosaic block, but are translated by a fixed vector with respect to each other. The observed structure is a weighted sum of the two identical but translated structures, one from each lattice; the observed structure factors are a weighted vector sum of the two structure factors with identical unit amplitudes but shifted phases. A general procedure is described to obtain the unit amplitudes of observed structure factors from a realigned single lattice through an X-ray intensity correction. An application of this procedure is made to determine the crystal structure of phi29 DNA polymerase at 2.2 A resolution using multiple isomorphous replacement and multiwavelength anomalous dispersion methods.
Wang
Jimin
J
Department of Molecular Biophysics and Biochemistry, Yale University, 266 Whitney Avenue, New Haven, CT 06520-8114, USA. wang@mail.csb.yale.edu
Kamtekar
Satwik
S
Berman
Andrea J
AJ
Steitz
Thomas A
TA
D017103:Bacillus Phages / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods*; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry*; D046911:Macromolecular Substances; D008958:Models, Molecular; D015233:Models, Statistical; D008968:Molecular Conformation; D011487:Protein Conformation; D012984:Software; D014961:X-Ray Diffraction; D014965:X-Rays
D046911:Macromolecular Substances; D004259:DNA-Directed DNA Polymerase