PDBsum entry 3cx6

Signaling protein

PDB id: 3cx6

Contents

Protein chains

320 a.a. *

185 a.a. *

Ligands

GDP

Metals

_MG

Waters ×145

* Residue conservation analysis

PDB id:

3cx6

Name:

Signaling protein

Title:

Crystal structure of pdzrhogef rgrgs domain in a complex with galpha- 13 bound to gdp

Structure:

Guanine nucleotide-binding protein alpha-13 subunit. Chain: a. Fragment: n-terminally truncated. Synonym: g alpha-13. Engineered: yes. Rho guanine nucleotide exchange factor 11. Chain: b. Fragment: rhogef-rgs (rgrgs) domain. Synonym: rhogef glutamate transport modulator gtrap48.

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: gna13, gna-13. Expressed in: spodoptera frugiperda. Rattus norvegicus. Rat. Organism_taxid: 10116. Gene: arhgef11.

Resolution:

2.50Å R-factor: 0.227 R-free: 0.285

Authors:

S.R.Sprang,Z.Chen

Key ref:

Z.Chen et al. (2008). Recognition of the activated states of Galpha13 by the rgRGS domain of PDZRhoGEF. Structure, 16, 1532-1543. PubMed id: 18940608 DOI: 10.1016/j.str.2008.07.009

Date:

23-Apr-08 Release date: 28-Oct-08

Protein chain

P27601  (GNA13_MOUSE) -  Guanine nucleotide-binding protein subunit alpha-13 from Mus musculus

Seq: 377 a.a.

Struc: 320 a.a.*

Protein chain

Q9ES67  (ARHGB_RAT) -  Rho guanine nucleotide exchange factor 11 from Rattus norvegicus

Seq: 1527 a.a.

Struc: 185 a.a.

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chains A, B: E.C.?

DOI no: 10.1016/j.str.2008.07.009

Structure 16:1532-1543 (2008)

PubMed id: 18940608

Recognition of the activated states of Galpha13 by the rgRGS domain of PDZRhoGEF.

Z.Chen, W.D.Singer, S.M.Danesh, P.C.Sternweis, S.R.Sprang.

ABSTRACT

G12 class heterotrimeric G proteins stimulate RhoA activation by RGS-RhoGEFs. However, p115RhoGEF is a GTPase Activating Protein (GAP) toward Galpha13, whereas PDZRhoGEF is not. We have characterized the interaction between the PDZRhoGEF rgRGS domain (PRG-rgRGS) and the alpha subunit of G13 and have determined crystal structures of their complexes in both the inactive state bound to GDP and the active states bound to GDP*AlF (transition state) and GTPgammaS (Michaelis complex). PRG-rgRGS interacts extensively with the helical domain and the effector-binding sites on Galpha13 through contacts that are largely conserved in all three nucleotide-bound states, although PRG-rgRGS has highest affinity to the Michaelis complex. An acidic motif in the N terminus of PRG-rgRGS occupies the GAP binding site of Galpha13 and is flexible in the GDP*AlF complex but well ordered in the GTPgammaS complex. Replacement of key residues in this motif with their counterparts in p115RhoGEF confers GAP activity.

Selected figure(s)

Figure 3.
Figure 3. GTPase Active Site in the PRG-rgRGS:Gα13•GDP•AlF[4]^− Complex
(A) Electron density (cages) at the active site from a 2.25 Å σ[A]−weighted 2F[o]−F[c] difference map (Read, 1986) is contoured at 1.6 standard deviations above the mean. Only densities of the PRG-rgRGS N terminus, GDP•Mg^2+•AlF[4]^− and the axial water molecule bound to AlF[4]^− are shown. Hydrogen bonds are drawn as dotted lines.
(B) Structural comparison of active sites from PRG-rgRGS:Gα13•GDP•AlF[4]^− complex and p115-rgRGS:Gα13/i1•GDP•AlF[4]^− complex. Elements from Gα13/i1 are colored gray and the N terminus of p115-rgRGS is colored brown.
(C) Stimulation of GTPase activity of Gα13 by increasing concentrations of wild-type and mutated PRG-rgRGS. Amino acids mutated in PRG-rgRGS are colored red.

Figure 5.
Figure 5. The Interface Between the RGS-Box and C-Terminal Extension of PRG-rgRGS and Gα13
(A) The solvent accessible surface of Gα13 is colored as in Figure 1C, with residues contacting the rgRGS colored blue. The RGS-box and C-terminal extension is colored green, with elements contacting Gα13 colored red.
(B) Residues of Gα13 that contact PRG-rgRGS are colored according to electrostatic potential as in Figure 2A. Side chains from PRG-rgRGS that directly contact Gα13 are represented as ball-and-stick models. In addition to the αE helix, the α3-α4 and α10-α11 loops of PRG-rgRGS also directly contact the effector-binding site of Gα13.
(C) Differences at the effector-binding site on Gα13 upon binding to PRG-rgRGS (left) or p115-rgRGS (right). Residues directly involved in the rgRGS:Gα13 interface are represented as ball-and-stick models.
(D) Ribbon diagram depicting the interaction interface between switch II of Gα13 and the N-terminal and the RGS-box subdomains of PRG-rgRGS. Main chain and side chain atoms are represented as ball-and-stick models. Hydrogen bonds are drawn as dotted lines.

The above figures are reprinted from an Open Access publication published by Cell Press: Structure (2008, 16, 1532-1543) copyright 2008.

Figures were selected by an automated process.