5T0R

Synaptotagmin 1 C2A domain, cadmium-bound

5T0R の概要

• エントリーDOI: 10.2210/pdb5t0r/pdb
• 関連するPDBエントリー: 5T0S
• 分子名称: Synaptotagmin-1, CADMIUM ION (3 entities in total)
• 機能のキーワード: metal binding protein
• 由来する生物種: Mus musculus (Mouse)
• 細胞内の位置: Cytoplasmic vesicle, secretory vesicle, synaptic vesicle membrane ; Single- pass membrane protein : P46096
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 14638.00

構造登録者

Taylor, A.B.,Hart, P.J.,Igumenova, T.I. (登録日: 2016-08-16, 公開日: 2017-06-14, 最終更新日: 2023-10-04)

主引用文献

Katti, S.,Nyenhuis, S.B.,Her, B.,Srivastava, A.K.,Taylor, A.B.,Hart, P.J.,Cafiso, D.S.,Igumenova, T.I.
Non-Native Metal Ion Reveals the Role of Electrostatics in Synaptotagmin 1-Membrane Interactions.
Biochemistry, 56:3283-3295, 2017

PubMed Abstract: C2 domains are independently folded modules that often target their host proteins to anionic membranes in a Ca-dependent manner. In these cases, membrane association is triggered by Ca binding to the negatively charged loop region of the C2 domain. Here, we used a non-native metal ion, Cd, in lieu of Ca to gain insight into the contributions made by long-range Coulombic interactions and direct metal ion-lipid bridging to membrane binding. Using X-ray crystallography, NMR, Förster resonance energy transfer, and vesicle cosedimentation assays, we demonstrate that, although Cd binds to the loop region of C2A/B domains of synaptotagmin 1 with high affinity, long-range Coulombic interactions are too weak to support membrane binding of individual domains. We attribute this behavior to two factors: the stoichiometry of Cd binding to the loop regions of the C2A and C2B domains and the impaired ability of Cd to directly coordinate the lipids. In contrast, electron paramagnetic resonance experiments revealed that Cd does support membrane binding of the C2 domains in full-length synaptotagmin 1, where the high local lipid concentrations that result from membrane tethering can partially compensate for lack of a full complement of divalent metal ions and specific lipid coordination in Cd-complexed C2A/B domains. Our data suggest that long-range Coulombic interactions alone can drive the initial association of C2A/B with anionic membranes and that Ca further augments membrane binding by the formation of metal ion-lipid coordination bonds and additional Ca ion binding to the C2 domain loop regions.

PubMed: 28574251
DOI: 10.1021/acs.biochem.7b00188

実験手法

X-RAY DIFFRACTION (1.95 Å)