[HIP_THETI] Specific class of high-redox-potential 4Fe-4S ferredoxins. Functions in anaerobic electron transport in most purple and in some other photosynthetic bacteria and in at least one genus (Paracoccus) of halophilic, denitrifying bacteria.
The positions of hydrogen atoms significantly define protein functions. However, such information from protein crystals is easily disturbed by X-rays. The damage can not be prevented completely even in the data collection at cryogenic temperatures. Therefore, the influence of X-rays should be precisely estimated in order to derive meaningful information from the crystallographic results. Diffraction data from a single crystal of the high-potential iron-sulfur protein (HiPIP) from Thermochromatium tepidum were collected at an undulator beamline of a third generation synchrotron facility, and were merged into three data sets according to X-ray dose. A series of structures analyzed at 0.70A shows detailed views of the X-ray induced perturbation, such as the positional changes of hydrogen atoms of a water molecule. Based on the results, we successfully collected a low perturbation data set using attenuated X-rays. There was no influence on the crystallographic statistics, such as the relative B factors, during the course of data collection. The electron densities for hydrogen atoms were more clear despite the slightly lower resolution.
Detailed assessment of X-ray induced structural perturbation in a crystalline state protein.,Takeda K, Kusumoto K, Hirano Y, Miki K J Struct Biol. 2010 Feb;169(2):135-44. Epub 2009 Sep 24. PMID:19782139
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Takeda K, Kusumoto K, Hirano Y, Miki K. Detailed assessment of X-ray induced structural perturbation in a crystalline state protein. J Struct Biol. 2010 Feb;169(2):135-44. Epub 2009 Sep 24. PMID:19782139 doi:10.1016/j.jsb.2009.09.012