Novel approach to phasing proteins: derivatization by short cryo-soaking with halides

• Published in: Acta crystallographica. Section D, Biological crystallography. Vol. 56; no. 2; pp. 232 - 237
• Main Authors: Dauter, Zbigniew, Dauter, Miroslawa, Rajashankar, K. R.
• Format: Journal Article
• Language: English
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England Munksgaard International Publishers 01-02-2000
• Subjects: Anions; anomalous scattering; bromide and iodide ions; Bromides - chemistry; Crystallization; Crystallography, X-Ray - methods; Freezing; Iodides - chemistry; MAD; Models, Molecular; Muramidase - chemistry; phasing; Protein Conformation; Proteins - chemistry; Ribonuclease, Pancreatic - chemistry; SAD; Scattering, Radiation; Solutions; Subtilisin - chemistry; Xylan Endo-1,3-beta-Xylosidase; Xylosidases - chemistry
• ISSN: 1399-0047; 0907-4449; 1399-0047
• DOI: 10.1107/S0907444999016352

A quick (less than 1 min) soak of protein crystals in a cryo‐solution containing bromide or iodide anions leads to incorporation of these anomalous scatterers into the ordered solvent region around the protein molecules. These halide anions provide a convenient way of phasing through their anomalous scattering signal: bromides using multiwavelength anomalous dispersion (MAD) and bromides and/or iodides using single‐wavelength anomalous dispersion (SAD) or single isomorphous replacement with anomalous scattering (SIRAS) methods. This approach has been tested successfully on four different proteins and has been used to solve the structure of a new protein of molecular weight 30 kDa.