PDBsum entry 1a2b

Oncogene protein

PDB id: 1a2b

Contents

Protein chain

178 a.a. *

Ligands

GSP

Metals

_MG

Waters ×38

* Residue conservation analysis

PDB id:

1a2b

Name:

Oncogene protein

Title:

Human rhoa complexed with gtp analogue

Structure:

Transforming protein rhoa. Chain: a. Fragment: residues 1 - 181. Engineered: yes. Mutation: yes. Other_details: complexed with one gtpgammas and one mg ion

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693.

Resolution:

2.40Å R-factor: 0.195 R-free: 0.268

Authors:

K.Ihara,S.Muraguchi,M.Kato,T.Shimizu,M.Shirakawa,S.Kuroda,K.Kaibuchi, T.Hakoshima

Key ref:

K.Ihara et al. (1998). Crystal structure of human RhoA in a dominantly active form complexed with a GTP analogue. J Biol Chem, 273, 9656-9666. PubMed id: 9545299 DOI: 10.1074/jbc.273.16.9656

Date:

26-Dec-97 Release date: 17-Jun-98

Protein chain

P61586  (RHOA_HUMAN) -  Transforming protein RhoA from Homo sapiens

Seq: 193 a.a.

Struc: 178 a.a.*

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

Enzyme reactions

• Enzyme class: 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(+)

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

reference

DOI no: 10.1074/jbc.273.16.9656

J Biol Chem 273:9656-9666 (1998)

PubMed id: 9545299

Crystal structure of human RhoA in a dominantly active form complexed with a GTP analogue.

K.Ihara, S.Muraguchi, M.Kato, T.Shimizu, M.Shirakawa, S.Kuroda, K.Kaibuchi, T.Hakoshima.

ABSTRACT

The 2.4-A resolution crystal structure of a dominantly active form of the small guanosine triphosphatase (GTPase) RhoA, RhoAV14, complexed with the nonhydrolyzable GTP analogue, guanosine 5'-3-O-(thio)triphosphate (GTPgammaS), reveals a fold similar to RhoA-GDP, which has been recently reported (Wei, Y., Zhang, Y., Derewenda, U., Liu, X., Minor, W., Nakamoto, R. K., Somlyo, A. V., Somlyo, A. P., and Derewenda, Z. S. (1997) Nat. Struct. Biol. 4, 699-703), but shows large conformational differences localized in switch I and switch II. These changes produce hydrophobic patches on the molecular surface of switch I, which has been suggested to be involved in its effector binding. Compared with H-Ras and other GTPases bound to GTP or GTP analogues, the significant conformational differences are located in regions involving switches I and II and part of the antiparallel beta-sheet between switches I and II. Key residues that produce these conformational differences were identified. In addition to these differences, RhoA contains four insertion or deletion sites with an extra helical subdomain that seems to be characteristic of members of the Rho family, including Rac1, but with several variations in details. These sites also display large displacements from those of H-Ras. The ADP-ribosylation residue, Asn41, by C3-like exoenzymes stacks on the indole ring of Trp58 with a hydrogen bond to the main chain of Glu40. The recognition of the guanosine moiety of GTPgammaS by the GTPase contains water-mediated hydrogen bonds, which seem to be common in the Rho family. These structural differences provide an insight into specific interaction sites with the effectors, as well as with modulators such as guanine nucleotide exchange factor (GEF) and guanine nucleotide dissociation inhibitor (GDI).

Selected figure(s)

Figure 4.
Fig. 4. GTP S bound to RhoA^V14. A cartoon of GTP S binding to RhoA^V14 with Mg2+ and water molecules. All dashed lines correspond to hydrogen bonding interactions (distance less than 3.5 Å), and the corresponding distances (Å) are indicated. The residues whose main chains participate in the hydrogen bonding are represented by rectangles, and the residues whose side chains participate in the hydrogen bonding are represented by ovals. The coordination bonds to the Mg2+ ion are indicated by arrows. The possible hydrogen bond between Gln63 and Wat-3 has a longer distance (3.8 Å). The hydrogen bonds observed in the current structure but not in H-Ras are highlighted in red.

Figure 6.
Fig. 6. Molecular surface of RhoA^V14. Residues whose mutations abolish the interaction with GEF are in yellow. Asn41 is also highlighted in green. Switches I and II are shown in red and blue, respectively. This surface also contains most of the residues corresponding to the effector-binding residues as seen in the complex between the Ras-binding domain of Raf1 and a double mutant Rap1A (E30D/K31E), which mimics Ras.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (1998, 273, 9656-9666) copyright 1998.

Figures were selected by an automated process.