Ultrahigh-resolution study on Pyrococcus abyssi rubredoxin. I. 0.69 A X-ray structure of mutant W4L/R5S.

The crystal structure of Pyrococcus abyssi rubredoxin mutant W4L/R5S was solved by direct methods. The model of the air-oxidized protein was refined by partially restrained full-matrix least-squares refinement against intensity data to 0.69 A resolution. This first ultrahigh-resolution structure of a rubredoxin provides very detailed and precise information about the Fe(SCys)(4) centre and its environment, the peptide-backbone stereochemistry, H atoms and hydrogen bonds, static and dynamic disorder, the solvent structure and the electron-density distribution. P. abyssi rubredoxin W4L/R5S is the first of a series of mutants studied by atomic and ultrahigh-resolution X-ray crystallography which are expected to contribute to the understanding of structure-function relationships in iron-sulfur proteins.