3ss8

Crystal structure of NFeoB from S. thermophilus bound to GDP.AlF4- and K+

spinqualitylabelsall models 3ss8, resolution 2.51Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3ss8 is a 2 chain structure with sequence from Streptococcus thermophilus LMG 18311. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.51Å Ligands: ALF, GDP, K, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q5M586_STRT2 Publication Abstract from PubMed The polytopic membrane protein FeoB is a ferrous iron transporter in prokaryotes. The protein contains a potassium-activated GTPase domain that is essential in regulating the import of iron and conferring virulence to many disease-causing bacteria. However, the mechanism by which the G-domain of FeoB hydrolyzes GTP is not well understood. In particular, it is not yet known how the pivotal step in GTP hydrolysis is achieved: alignment of a catalytic water molecule. In the current study, the crystal structure of the soluble domains from Streptococcus thermophilus FeoB (NFeoB(St)) in complex with the activating potassium ion and a transition-state analogue, GDPAlF(4) (-), reveals a novel mode of water alignment involving contacts with the protein backbone only. In parallel to the structural studies, a series of seven mutant proteins were constructed that targeted conserved residues at the active site of NFeoB(St), and the nucleotide binding and hydrolysis properties of these were measured and compared to the wild-type protein. The results show that mutations in Thr35 abolish GTPase activity of the protein, while other conserved residues (Tyr58, Ser64, Glu66 and Glu67) are not required for water alignment by NFeoB(St). Together with the crystal structure, the findings suggest a new mechanism for hydrolysis initiation in small G-proteins, in which the attacking water molecule is aligned by contacts with the protein backbone only. The initiation of GTP hydrolysis by the G-domain of FeoB: insights from a transition-state complex structure.,Ash MR, Maher MJ, Guss JM, Jormakka M PLoS One. 2011;6(8):e23355. Epub 2011 Aug 9. PMID:21858085 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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