PDBsum entry 4l12

Calcium binding protein

PDB id: 4l12

Contents

Protein chain

230 a.a.

Metals

_GD ×2

Waters ×138

PDB id:

4l12

Name:

Calcium binding protein

Title:

Crystal structure of egfp-based calcium sensor catcher complexed with gd

Structure:

Egfp-based calcium sensor catcher. Chain: a. Fragment: see remark 999. Synonym: green fluorescent protein. Engineered: yes. Mutation: yes

Source:

Aequorea victoria. Jellyfish. Organism_taxid: 6100. Gene: gfp. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.78Å R-factor: 0.197 R-free: 0.220

Authors:

Y.Zhang,I.T.Weber

Key ref:

Y.Zhang et al. (2013). Structural basis for a hand-like site in the calcium sensor CatchER with fast kinetics. Acta Crystallogr D Biol Crystallogr, 69, 2309-2319. PubMed id: 24311573 DOI: 10.1107/S0907444913021306

Date:

01-Jun-13 Release date: 11-Dec-13

Protein chain

P42212  (GFP_AEQVI) -  Green fluorescent protein from Aequorea victoria

Seq: 238 a.a.

Struc: 230 a.a.*

* PDB and UniProt seqs differ at 11 residue positions (black crosses)

DOI no: 10.1107/S0907444913021306

Acta Crystallogr D Biol Crystallogr 69:2309-2319 (2013)

PubMed id: 24311573

Structural basis for a hand-like site in the calcium sensor CatchER with fast kinetics.

Y.Zhang, F.Reddish, S.Tang, Y.Zhuo, Y.F.Wang, J.J.Yang, I.T.Weber.

ABSTRACT

Calcium ions, which are important signaling molecules, can be detected in the endoplasmic reticulum by an engineered mutant of green fluorescent protein (GFP) designated CatchER with a fast off-rate. High resolution (1.78-1.20 Å) crystal structures were analyzed for CatchER in the apo form and in complexes with calcium or gadolinium to probe the binding site for metal ions. While CatchER exhibits a 1:1 binding stoichiometry in solution, two positions were observed for each of the metal ions bound within the hand-like site formed by the carboxylate side chains of the mutated residues S147E, S202D, Q204E, F223E and T225E that may be responsible for its fast kinetic properties. Comparison of the structures of CatchER, wild-type GFP and enhanced GFP confirmed that different conformations of Thr203 and Glu222 are associated with the two forms of Tyr66 of the chromophore which are responsible for the absorbance wavelengths of the different proteins. Calcium binding to CatchER may shift the equilibrium for conformational population of the Glu222 side chain and lead to further changes in its optical properties.