3D7M

Crystal Structure of the G Protein Fast-Exchange Double Mutant I56C/Q333C

3D7M の概要

• エントリーDOI: 10.2210/pdb3d7m/pdb
• 関連するPDBエントリー: 1BH2 1GFI 1Y3A 2G83 2HLB
• 分子名称: Guanine nucleotide-binding protein G(i), alpha-1 subunit, MAGNESIUM ION, TETRAFLUOROALUMINATE ION, ... (5 entities in total)
• 機能のキーワード: nucleotide binding, allosteric, gtp-binding, lipoprotein, myristate, nucleotide-binding, palmitate, transducer, signaling protein
• 由来する生物種: Rattus norvegicus (rat)
• 細胞内の位置: Nucleus: P10824
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 40934.51

構造登録者

Funk, M.A.,Preininger, A.M.,Oldham, W.M.,Meier, S.M.,Hamm, H.E.,Iverson, T.M. (登録日: 2008-05-21, 公開日: 2009-03-03, 最終更新日: 2024-11-13)

主引用文献

Preininger, A.M.,Funk, M.A.,Oldham, W.M.,Meier, S.M.,Johnston, C.A.,Adhikary, S.,Kimple, A.J.,Siderovski, D.P.,Hamm, H.E.,Iverson, T.M.
Helix dipole movement and conformational variability contribute to allosteric GDP release in Galphai subunits.
Biochemistry, 48:2630-2642, 2009

PubMed Abstract: Heterotrimeric G proteins (Galphabetagamma) transmit signals from activated G protein-coupled receptors (GPCRs) to downstream effectors through a guanine nucleotide signaling cycle. Numerous studies indicate that the carboxy-terminal alpha5 helix of Galpha subunits participates in Galpha-receptor binding, and previous EPR studies suggest this receptor-mediated interaction induces a rotation and translation of the alpha5 helix of the Galpha subunit [Oldham, W. M., et al. (2006) Nat. Struct. Mol. Biol. 13, 772-777]. On the basis of this result, an engineered disulfide bond was designed to constrain the alpha5 helix of Galpha(i1) into its EPR-measured receptor-associated conformation through the introduction of cysteines at position 56 in the alpha1 helix and position 333 in the alpha5 helix (I56C/Q333C Galpha(i1)). A functional mimetic of the EPR-measured alpha5 helix dipole movement upon receptor association was additionally created by introduction of a positive charge at the amino terminus of this helix, D328R Galpha(i1). Both proteins exhibit a dramatically elevated level of basal nucleotide exchange. The 2.9 A resolution crystal structure of I56C/Q333C Galpha(i1) in complex with GDP-AlF(4)(-) reveals the shift of the alpha5 helix toward the guanine nucleotide binding site that is anticipated by EPR measurements. The structure of the I56C/Q333C Galpha(i1) subunit further revealed altered positions for the switch regions and throughout the Galpha(i1) subunit, accompanied by significantly elevated crystallographic temperature factors. Combined with previous evidence in the literature, the structural analysis supports the critical role of electrostatics of the alpha5 helix dipole and overall conformational variability during nucleotide release.

PubMed: 19222191
DOI: 10.1021/bi801853a

実験手法

X-RAY DIFFRACTION (2.9 Å)