PDBsum entry: 1n4k

Membrane protein

PDB id: 1n4k

Contents

Protein chain

292 a.a. *

Ligands

I3P

Waters ×140

* Residue conservation analysis

PDB id:

1n4k

Name:

Membrane protein

Title:

Crystal structure of the inositol 1,4,5-trisphosphate receptor binding core in complex with ip3

Structure:

Inositol 1,4,5-trisphosphate receptor type 1. Chain: a. Fragment: ip3-binding core. Synonym: type 1 inositol 1,4,5- trisphosphate receptor, type 1 insp3 receptor, ip3 receptor isoform 1, insp3r1, inositol 1,4,5-trisphosphate-binding protein p400, purkinje cell protein 1. Engineered: yes

Source:

Mus musculus. House mouse. Organism_taxid: 10090. Gene: itpr1 or insp3r. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.20Å R-factor: 0.224 R-free: 0.248

Authors:

I.Bosanac,J.R.Alattia,T.K.Mal,J.Chan,S.Talarico,F.K.Tong, K.I.Tong,F.Yoshikawa,T.Furuichi,M.Iwai,T.Michikawa, K.Mikoshiba,M.Ikura

Key ref:

I.Bosanac et al. (2002). Structure of the inositol 1,4,5-trisphosphate receptor binding core in complex with its ligand. Nature, 420, 696-700. PubMed id: 12442173 DOI: 10.1038/nature01268

Date:

31-Oct-02 Release date: 25-Dec-02

Protein chain

P11881  (ITPR1_MOUSE) -  Inositol 1,4,5-trisphosphate receptor type 1

Seq: 2749 a.a.

Struc: 292 a.a.

 Gene Ontology (GO) functional annotation 

• Cellular component: membrane (2 terms)
• Biological process: calcium ion transport (1 term)
• Biochemical function: calcium channel activity (2 terms)

DOI no: 10.1038/nature01268

Nature 420:696-700 (2002)

PubMed id: 12442173

Structure of the inositol 1,4,5-trisphosphate receptor binding core in complex with its ligand.

I.Bosanac, J.R.Alattia, T.K.Mal, J.Chan, S.Talarico, F.K.Tong, K.I.Tong, F.Yoshikawa, T.Furuichi, M.Iwai, T.Michikawa, K.Mikoshiba, M.Ikura.

ABSTRACT

In a variety of cells, the Ca2+ signalling process is mediated by the endoplasmic-reticulum-membrane-associated Ca2+ release channel, inositol 1,4,5-trisphosphate (InsP3) receptor (InsP3R). Being ubiquitous and present in organisms ranging from humans to Caenorhabditis elegans, InsP3R has a vital role in the control of cellular and physiological processes as diverse as cell division, cell proliferation, apoptosis, fertilization, development, behaviour, memory and learning. Mouse type I InsP3R (InsP3R1), found in high abundance in cerebellar Purkinje cells, is a polypeptide with three major functionally distinct regions: the amino-terminal InsP3-binding region, the central modulatory region and the carboxy-terminal channel region. Here we present a 2.2-A crystal structure of the InsP3-binding core of mouse InsP3R1 in complex with InsP3. The asymmetric, boomerang-like structure consists of an N-terminal beta-trefoil domain and a C-terminal alpha-helical domain containing an 'armadillo repeat'-like fold. The cleft formed by the two domains exposes a cluster of arginine and lysine residues that coordinate the three phosphoryl groups of InsP3. Putative Ca2+-binding sites are identified in two separate locations within the InsP3-binding core.

Selected figure(s)

Figure 2.
Figure 2: Structure of mouse InsP[3]R1[c] in complex with InsP[3]. a, The -domain (yellow) and the -domain (green) with the InsP[3] molecule at the interface. Residues in the Ca-I and Ca-II sites and the splicing site (SI) are shown. b, View in a rotated by 180°. c, Experimental MAD electron density map at 1.7 around the InsP[3] molecule. d, e, Molecular surface representations of mouse InsP[3]R1[c] in the same orientations as a and b, respectively. Surface electrostatic potential (left panel with Ca-I and Ca-II sites) and conserved surface residues (right panel with P-I, P-II sites; identical residues are shown in red, and least-conserved residues in white).

Figure 4.
Figure 4: Coordination of InsP[3] by mouse InsP[3]R1[c]. Ribbon representation of the polypeptide chains of the -domain (green) and the -domain (yellow). Phosphates are shown in yellow, oxygens in red, nitrogens in blue, water molecules in cyan, and hydrogen bonds with dotted black lines. The coordination of P1 and P5 groups is shown in a, and that of P4 in b. c, Two-dimensional schematic representation of the interaction of mouse InsP[3]R1[c] with InsP[3]. d, Graph showing average specific InsP[3]-binding activity of site-directed mutant from a minimum of four independent experiments.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nature (2002, 420, 696-700) copyright 2002.

Figures were selected by an automated process.