X-ray damage to the Mn4Ca complex in single crystals of photosystem II: a case study for metalloprotein crystallography.

ABSTRACT: X-ray absorption spectroscopy was used to measure the damage caused by exposure to x-rays to the Mn(4)Ca active site in single crystals of photosystem II as a function of dose and energy of x-rays, temperature, and time. These studies reveal that the conditions used for structure determination by x-ray crystallography cause serious damage specifically to the metal-site structure. The x-ray absorption spectra show that the structure changes from one that is characteristic of a high-valent Mn(4)(III(2),IV(2)) oxo-bridged Mn(4)Ca cluster to that of Mn(II) in aqueous solution. This damage to the metal site occurs at a dose that is more than one order of magnitude lower than the dose that results in loss of diffractivity and is commonly considered safe for protein crystallography. These results

SUBMITTER: Yano J 

PROVIDER: S-EPMC1186027 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature