PDBsum entry 2e30

Metal binding protein/transport protein

PDB id: 2e30

Contents

Protein chains

195 a.a. *

43 a.a. *

Metals

_CA ×2

* Residue conservation analysis

PDB id:

2e30

Name:

Metal binding protein/transport protein

Title:

Solution structure of the cytoplasmic region of na+/h+ exchanger 1 complexed with essential cofactor calcineurin b homologous protein 1

Structure:

Calcium-binding protein p22. Chain: a. Synonym: calcium-binding protein chp, calcineurin homologous protein, calcineurin b homolog. Engineered: yes. Sodium/hydrogen exchanger 1. Chain: b. Fragment: nhe1 fragment (503-545). Synonym: na+, /h+, exchanger 1, nhe-1, solute carrier family 9 member

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: chp1. Expressed in: escherichia coli. Expression_system_taxid: 511693.

NMR struc:

20 models

Authors:

M.Mishima,S.Wakabayashi,C.Kojima

Key ref:

M.Mishima et al. (2007). Solution structure of the cytoplasmic region of Na+/H+ exchanger 1 complexed with essential cofactor calcineurin B homologous protein 1. J Biol Chem, 282, 2741-2751. PubMed id: 17050540 DOI: 10.1074/jbc.M604092200

Date:

19-Nov-06 Release date: 19-Dec-06

Protein chain

Q99653  (CHP1_HUMAN) -  Calcineurin B homologous protein 1 from Homo sapiens

Seq: 195 a.a.

Struc: 195 a.a.

Protein chain

P19634  (SL9A1_HUMAN) -  Sodium/hydrogen exchanger 1 from Homo sapiens

Seq: 815 a.a.

Struc: 43 a.a.

DOI no: 10.1074/jbc.M604092200

J Biol Chem 282:2741-2751 (2007)

PubMed id: 17050540

Solution structure of the cytoplasmic region of Na+/H+ exchanger 1 complexed with essential cofactor calcineurin B homologous protein 1.

M.Mishima, S.Wakabayashi, C.Kojima.

ABSTRACT

Na+/H+ exchanger 1 (NHE1) regulates intracellular pH, Na+ content, and cell volume. Calcineurin B homologous protein 1 (CHP1) serves as an essential cofactor that facilitates NHE1 exchange activity under physiological conditions by direct binding to the cytoplasmic juxtamembrane region of NHE1. Here we describe the solution structure of the cytoplasmic juxtamembrane region of NHE1 complexed with CHP1. The region of NHE1 forms an amphipathic helix, which is induced by CHP1 binding, and CHP1 possesses a large hydrophobic cleft formed by EF-hand helices. The apolar side of the NHE1 helix participates in extensive hydrophobic interactions with the cleft of CHP1. We suggest that helix formation of the cytoplasmic region of NHE1 by CHP1 is a prerequisite for generating the active form of NHE1. The molecular recognition detailed in this study also provides novel insight into the target binding mechanism of EF-hand proteins.

Selected figure(s)

Figure 3.
FIGURE 3. Solution structure of the NHE1-CHP1 complex. A, stereoview of the backbone superpositions of the final 20 simulated annealing structures of the NHE1-CHP1 complex. B, ribbon drawing of the representative NHE1-CHP1 structure complex. A and B, residues 517–538 of NHE1 and 10–192 of CHP1 are shown. The N- and C-terminal domains of CHP1 are colored in blue and magenta, respectively, and the CHP loop is colored in gray. NHE1 is shown in green.Ca^2+ ions are shown by gold spheres.

Figure 4.
FIGURE 4. Molecular surface of the NHE1-CHP1 complex. A, molecular surface of CHP1 and backbone tube representation of NHE1 with yellow stick that shows the hydrophobic side chains. The N- and C-terminal domains of CHP1 are colored in blue and magenta, respectively. B, molecular surface of NHE1 and backbone tube representation of CHP1. Hydrophobic, acidic, and polar residues are colored in yellow, red, and blue, respectively.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 2741-2751) copyright 2007.

Figures were selected by the author.