3LX5

Crystal structure of mGMPPNP-bound NFeoB from S. thermophilus

3LX5 の概要

• エントリーDOI: 10.2210/pdb3lx5/pdb
• 関連するPDBエントリー: 3LX8
• 分子名称: Ferrous iron uptake transporter protein B, 2-amino-9-(5-O-[(R)-hydroxy{[(R)-hydroxy(phosphonoamino)phosphoryl]oxy}phosphoryl]-3-O-{[2-(methylamino)phenyl]carbonyl}-beta-D-erythro-pentofuranosyl-2-ulose)-1,9-dihydro-6H-purin-6-one, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: g protein, iron transport, gtp-binding, gtpase, transmembrane, nucleotide-binding, metal transport
• 由来する生物種: Streptococcus thermophilus
• 細胞内の位置: Cell membrane : Q5M586
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 30972.88

構造登録者

Ash, M.R.,Guilfoyle, A.,Maher, M.J.,Clarke, R.J.,Guss, J.M.,Jormakka, M. (登録日: 2010-02-24, 公開日: 2010-03-09, 最終更新日: 2023-11-01)

主引用文献

Ash, M.R.,Guilfoyle, A.,Clarke, R.J.,Guss, J.M.,Maher, M.J.,Jormakka, M.
Potassium-activated GTPase reaction in the G Protein-coupled ferrous iron transporter B.
J.Biol.Chem., 285:14594-14602, 2010

PubMed Abstract: FeoB is a prokaryotic membrane protein responsible for the import of ferrous iron (Fe(2+)). A defining feature of FeoB is that it includes an N-terminal 30-kDa soluble domain with GTPase activity, which is required for iron transport. However, the low intrinsic GTP hydrolysis rate of this domain appears to be too slow for FeoB either to function as a channel or to possess an active Fe(2+) membrane transport mechanism. Here, we present crystal structures of the soluble domain of FeoB from Streptococcus thermophilus in complex with GDP and with the GTP analogue derivative 2'-(or -3')-O-(N-methylanthraniloyl)-beta,gamma-imidoguanosine 5'-triphosphate (mant-GMPPNP). Unlike recent structures of the G protein domain, the mant-GMPPNP-bound structure shows clearly resolved, active conformations of the critical Switch motifs. Importantly, biochemical analyses demonstrate that the GTPase activity of FeoB is activated by K(+), which leads to a 20-fold acceleration in its hydrolysis rate. Analysis of the structure identified a conserved asparagine residue likely to be involved in K(+) coordination, and mutation of this residue abolished K(+)-dependent activation. We suggest that this, together with a second asparagine residue that we show is critical for the structure of the Switch I loop, allows the prediction of K(+)-dependent activation in G proteins. In addition, the accelerated hydrolysis rate opens up the possibility that FeoB might indeed function as an active transporter.

PubMed: 20220129
DOI: 10.1074/jbc.M110.111914

実験手法

X-RAY DIFFRACTION (1.9 Å)