MAD phasing with krypton
| Autor: | Paul J. Ellis, S.M. Soltis, Aina E. Cohen, Nicole Kresge |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Xenon
Protein Conformation Analytical chemistry chemistry.chemical_element Synchrotron radiation Crystallography X-Ray chemistry.chemical_compound Structural Biology Animals Derivatization Myoglobin Krypton Whales Proteins General Medicine Molecular Weight Crystallography K-edge Beamline chemistry Mollusca Protein crystallization Single crystal Software |
| Zdroj: | Acta Crystallographica Section D Biological Crystallography. 57:233-238 |
| ISSN: | 0907-4449 |
| DOI: | 10.1107/s0907444900014670 |
| Popis: | Experiments demonstrating the feasibility of Kr-edge MAD on frozen crystals as a routine method for structure determination are reported. Approximately 50% of protein crystals can be successfully derivatized by pressurization with the noble gases xenon or krypton. While Xe has produced many useful derivatives for MIR phasing over the last several years, the Xe edges (K edge = 34.6 keV, L(I) = 5.5 keV) are not easily accessible for MAD studies. As the Kr K edge (14.3 keV) is accessible on most MAD beamlines, Kr derivatization provides the additional opportunity to conduct a MAD experiment and obtain phases using only a single crystal. This paper describes the phasing of two proteins using Kr MAD: the 17 kDa Fe protein myoglobin (Mb) from sperm whale (Physeter catodon) and an 18 kDa protein (SP18) from green abalone (Haliotis fulgens). Three-wavelength data were collected at SSRL beamline 9-2 from crystals of Mb and SP18 incubated in 2.76 MPa of Kr gas for 2 min, depressurized and then flash-frozen in a stream of nitrogen gas at 100 K. MAD phases were calculated using the program SHARP and the resulting density improved with wARP. The final maps for both Mb and SP18 were of excellent quality. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text