Filter
Associated Lab
- Ahrens Lab (4) Apply Ahrens Lab filter
- Betzig Lab (1) Apply Betzig Lab filter
- Druckmann Lab (1) Apply Druckmann Lab filter
- Harris Lab (4) Apply Harris Lab filter
- Hermundstad Lab (1) Apply Hermundstad Lab filter
- Jayaraman Lab (9) Apply Jayaraman Lab filter
- Karpova Lab (1) Apply Karpova Lab filter
- Lavis Lab (5) Apply Lavis Lab filter
- Leonardo Lab (1) Apply Leonardo Lab filter
- Liu (Zhe) Lab (1) Apply Liu (Zhe) Lab filter
- Looger Lab (24) Apply Looger Lab filter
- Podgorski Lab (5) Apply Podgorski Lab filter
- Rubin Lab (1) Apply Rubin Lab filter
- Schreiter Lab (42) Apply Schreiter Lab filter
- Svoboda Lab (13) Apply Svoboda Lab filter
- Tillberg Lab (1) Apply Tillberg Lab filter
- Turner Lab (3) Apply Turner Lab filter
- Zlatic Lab (1) Apply Zlatic Lab filter
Associated Project Team
Publication Date
- 2023 (6) Apply 2023 filter
- 2021 (1) Apply 2021 filter
- 2020 (5) Apply 2020 filter
- 2019 (4) Apply 2019 filter
- 2018 (4) Apply 2018 filter
- 2017 (4) Apply 2017 filter
- 2016 (2) Apply 2016 filter
- 2015 (4) Apply 2015 filter
- 2013 (5) Apply 2013 filter
- 2012 (2) Apply 2012 filter
- 2011 (2) Apply 2011 filter
- 2009 (2) Apply 2009 filter
- 2008 (1) Apply 2008 filter
Type of Publication
- Remove Janelia filter Janelia
42 Publications
Showing 41-42 of 42 resultsThe 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.
Fluorescent proteins and their engineered variants have played an important role in the study of biology. The genetically encoded calcium-indicator protein GCaMP2 comprises a circularly permuted fluorescent protein coupled to the calcium-binding protein calmodulin and a calmodulin target peptide, M13, derived from the intracellular calmodulin target myosin light-chain kinase and has been used to image calcium transients in vivo. To aid rational efforts to engineer improved variants of GCaMP2, this protein was crystallized in the calcium-saturated form. X-ray diffraction data were collected to 2.0 A resolution. The crystals belong to space group C2, with unit-cell parameters a = 126.1.