3EK8

Calcium-saturated GCaMP2 T116V/G87R mutant monomer

3EK8 の概要

• エントリーDOI: 10.2210/pdb3ek8/pdb
• 関連するPDBエントリー: 3EK4 3EK7 3EKH 3EKJ
• 分子名称: Myosin light chain kinase, Green fluorescent protein, Calmodulin chimera, CALCIUM ION (3 entities in total)
• 機能のキーワード: geci, gcamp2, cpegfp, calmodulin, m13 peptide, signaling protein, fluorescent protein
• 由来する生物種: artificial gene; 詳細
• 細胞内の位置: Cytoplasm, cytoskeleton, spindle: P0DP29
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 50963.07

構造登録者

Akerboom, J.,Velez Rivera, J.D.,Looger, L.L.,Schreiter, E.R. (登録日: 2008-09-19, 公開日: 2008-12-16, 最終更新日: 2024-10-09)

主引用文献

Akerboom, J.,Rivera, J.D.,Guilbe, M.M.,Malave, E.C.,Hernandez, H.H.,Tian, L.,Hires, S.A.,Marvin, J.S.,Looger, L.L.,Schreiter, E.R.
Crystal Structures of the GCaMP Calcium Sensor Reveal the Mechanism of Fluorescence Signal Change and Aid Rational Design
J.Biol.Chem., 284:6455-6464, 2009

PubMed Abstract: The genetically encoded calcium indicator GCaMP2 shows promise for neural network activity imaging, but is currently limited by low signal-to-noise ratio. We describe x-ray crystal structures as well as solution biophysical and spectroscopic characterization of GCaMP2 in the calcium-free dark state, and in two calcium-bound bright states: a monomeric form that dominates at intracellular concentrations observed during imaging experiments and an unexpected domain-swapped dimer with decreased fluorescence. This series of structures provides insight into the mechanism of Ca2+-induced fluorescence change. Upon calcium binding, the calmodulin (CaM) domain wraps around the M13 peptide, creating a new domain interface between CaM and the circularly permuted enhanced green fluorescent protein domain. Residues from CaM alter the chemical environment of the circularly permuted enhanced green fluorescent protein chromophore and, together with flexible inter-domain linkers, block solvent access to the chromophore. Guided by the crystal structures, we engineered a series of GCaMP2 point mutants to probe the mechanism of GCaMP2 function and characterized one mutant with significantly improved signal-to-noise. The mutation is located at a domain interface and its effect on sensor function could not have been predicted in the absence of structural data.

PubMed: 19098007
DOI: 10.1074/jbc.M807657200

実験手法

X-RAY DIFFRACTION (2.8 Å)