Open AccessThe structure of an N11A mutant of the G‐protein domain of FeoB
Author(s) -
Ash MiriamRose,
Maher Megan J.,
Guss J. Mitchell,
Jormakka Mika
Publication year - 2011
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309111042965
Subject(s) - gtpase , mutant , gtp' , chemistry , nucleotide , crystallography , residue (chemistry) , asparagine , protein structure , mutant protein , cyclic nucleotide binding domain , biochemistry , g protein , stereochemistry , amino acid , enzyme , gene , receptor
The uptake of ferrous iron in prokaryotes is mediated by the G‐protein‐coupled membrane protein FeoB. The protein contains two N‐terminal soluble domains that are together called `NFeoB'. One of these is a G‐protein domain, and GTP hydrolysis by this domain is essential for iron transport. The GTPase activity of NFeoB is accelerated in the presence of potassium ions, which bind at a site adjacent to the nucleotide. One of the ligands at the potassium‐binding site is a conserved asparagine residue, which corresponds to Asn11 in Streptococcus thermophilus NFeoB. The structure of an N11A S. thermophilus NFeoB mutant has been determined and refined to a resolution of 1.85 Å; the crystals contained a mixture of mant‐GDP‐bound and mant‐GMP‐bound protein. The structure demonstrates how the use of a derivatized nucleotide in cocrystallization experiments can facilitate the growth of diffraction‐quality crystals.