PDBsum entry 2fju

Signaling protein,apoptosis/hydrolase

PDB id: 2fju

Contents

Protein chains

177 a.a. *

696 a.a. *

Ligands

GSP

Metals

_CA

_MG

Waters ×486

* Residue conservation analysis

PDB id:

2fju

Name:

Signaling protein,apoptosis/hydrolase

Title:

Activated rac1 bound to its effector phospholipasE C beta 2

Structure:

Ras-related c3 botulinum toxin substrate 1. Chain: a. Fragment: residues 1-189. Synonym: p21-rac1. Ras-like protein tc25. Engineered: yes. 1-phosphatidylinositol-4,5-bisphosphate phosphodiesterase beta 2. Chain: b. Fragment: residues 1-799.

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: rac1. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: plcb2. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108.

Biol. unit:

Dimer (from PQS)

Resolution:

2.20Å R-factor: 0.208 R-free: 0.226

Authors:

M.R.Jezyk,J.T.Snyder,T.K.Harden,J.Sondek

Key ref:

M.R.Jezyk et al. (2006). Crystal structure of Rac1 bound to its effector phospholipase C-beta2. Nat Struct Mol Biol, 13, 1135-1140. PubMed id: 17115053 DOI: 10.1038/nsmb1175

Date:

03-Jan-06 Release date: 21-Nov-06

Protein chain

P63000  (RAC1_HUMAN) -  Ras-related C3 botulinum toxin substrate 1 from Homo sapiens

Seq: 192 a.a.

Struc: 177 a.a.

Protein chain

Q00722  (PLCB2_HUMAN) -  1-phosphatidylinositol 4,5-bisphosphate phosphodiesterase beta-2 from Homo sapiens

Seq: 1185 a.a.

Struc: 696 a.a.

Enzyme reactions

• Enzyme class 2: Chain A: E.C.3.6.5.2 - small monomeric GTPase.
• Reaction: GTP + H2O = GDP + phosphate + H⁺

GTP (Bound ligand (Het Group name = GSP) matches with 93.94% similarity) + H2O = GDP + phosphate + H(+)

• Enzyme class 3: Chain B: E.C.3.1.4.11 - phosphoinositide phospholipase C.

Pathway:

• Reaction: a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-4,5-bisphosphate) + H2O = 1D-myo-inositol 1,4,5-trisphosphate + a 1,2-diacyl-sn-glycerol + H⁺

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1038/nsmb1175

Nat Struct Mol Biol 13:1135-1140 (2006)

PubMed id: 17115053

Crystal structure of Rac1 bound to its effector phospholipase C-beta2.

M.R.Jezyk, J.T.Snyder, S.Gershberg, D.K.Worthylake, T.K.Harden, J.Sondek.

ABSTRACT

Although diverse signaling cascades require the coordinated regulation of heterotrimeric G proteins and small GTPases, these connections remain poorly understood. We present the crystal structure of the GTPase Rac1 bound to phospholipase C-beta2 (PLC-beta2), a classic effector of heterotrimeric G proteins. Rac1 engages the pleckstrin-homology (PH) domain of PLC-beta2 to optimize its orientation for substrate membranes. Gbetagamma also engages the PH domain to activate PLC-beta2, and these two activation events are compatible, leading to additive stimulation of phospholipase activity. In contrast to PLC-delta, the PH domain of PLC-beta2 cannot bind phosphoinositides, eliminating this mode of regulation. The structure of the Rac1-PLC-beta2 complex reveals determinants that dictate selectivity of PLC-beta isozymes for Rac GTPases over other Rho-family GTPases, and substitutions within PLC-beta2 abrogate its stimulation by Rac1 but not by Gbetagamma, allowing for functional dissection of this integral signaling node.

Selected figure(s)

Figure 1.
Figure 1. Structure of activated Rac1 in complex with PLC- 2. (a) Domain architecture of PLC- 2. PLC- 2 has the conserved core of all PLC enzymes, which includes an N-terminal PH domain followed by four EF hands, a catalytic TIM barrel and a C2 domain. PLC- isozymes elaborate this core with a C-terminal coiled-coil domain (CT), which mediates homodimerization and phospholipase stimulation by G q. This region, which is not necessary for Rac activation, was removed to facilitate crystallization, by truncation of PLC- 2 at residue 799 (arrow). (b) Ribbon diagram of overall structure of Rac1 bound to the conserved core of PLC- 2, as viewed from below the plane of the membrane. Activated Rac1, bound to the nonhydrolyzable GTP analog GTP- S (cyan), engages solely the PH domain of PLC- 2. Switch regions (Sw1, Sw2) are also indicated (red). (c) View rotated about the x-axis by 90°, showing membrane-anchored orientation of the Rac1–PLC- 2 complex. The geranylgeranylated C terminus of Rac1 and the substrate of PLC- 2, PI(4,5)P[2], are modeled as sites of membrane attachment.

Figure 2.
Figure 2. Intermolecular interface of Rac1 and PLC- 2. (a) Surface representation and schematic of the PH domain of PLC- 2 (gray) engaging the switch regions of Rac1 (red). Contact residues of the PH domain are highlighted (blue). (b) Close-up view of a highlighting intermolecular contacts. Gln52 and Tyr118 of PLC- 2 form central points of the interface and are stabilized by a tight network of hydrogen bonds and -orbital interactions.

The above figures are reprinted by permission from Macmillan Publishers Ltd: Nat Struct Mol Biol (2006, 13, 1135-1140) copyright 2006.

Figures were selected by an automated process.