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Rapid cadmium SAD phasing at the standard wavelength (1 Å)
Author(s) -
Panneerselvam Saravanan,
Kumpula Esa-Pekka,
Kursula Inari,
Burkhardt Anja,
Meents Alke
Publication year - 2017
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.374
H-Index - 138
ISSN - 2059-7983
DOI - 10.1107/s2059798317006970
Subject(s) - phaser , ion , anomalous scattering , cadmium , wavelength , divalent , materials science , chemistry , crystallography , physics , diffraction , optoelectronics , optics , organic chemistry , metallurgy
Cadmium ions can be effectively used to promote crystal growth and for experimental phasing. Here, the use of cadmium ions as a suitable anomalous scatterer at the standard wavelength of 1 Å is demonstrated. The structures of three different proteins were determined using cadmium single‐wavelength anomalous dispersion (SAD) phasing. Owing to the strong anomalous signal, the structure of lysozyme could be automatically phased and built using a very low anomalous multiplicity (1.1) and low‐completeness (77%) data set. Additionally, it is shown that cadmium ions can easily substitute divalent ions in ATP–divalent cation complexes. This property could be generally applied for phasing experiments of a wide range of nucleotide‐binding proteins. Improvements in crystal growth and quality, good anomalous signal at standard wavelengths ( i.e. no need to change photon energy) and rapid phasing and refinement using a single data set are benefits that should allow cadmium ions to be widely used for experimental phasing.