2JOK

NMR structure of the catalytic domain of guanine nucleotide exchange factor BopE from Burkholderia pseudomallei

Summary for 2JOK

• Entry DOI: 10.2210/pdb2jok/pdb
• Related: 1GZS 1R6E 1R9K 2JOL
• Descriptor: Putative G-nucleotide exchange factor (1 entity in total)
• Functional Keywords: guanine nucleotide exchange factor, burkholderia pseudomallei, type iii secretion, sope, sope2, cell invasion, signaling protein
• Biological source: Burkholderia pseudomallei
• Cellular location: Secreted: Q63K41
• Total number of polymer chains: 1
• Total formula weight: 20136.34

Authors

Wu, H.,Upadhyay, A.,Williams, C.,Galyov, E.E.,van den Elsen, J.M.H.,Bagby, S. (deposition date: 2007-03-14, release date: 2007-09-18, Last modification date: 2023-12-20)

Primary citation

Upadhyay, A.,Wu, H.L.,Williams, C.,Field, T.,Galyov, E.E.,van den Elsen, J.M.,Bagby, S.
The guanine-nucleotide-exchange factor BopE from Burkholderia pseudomallei adopts a compact version of the Salmonella SopE/SopE2 fold and undergoes a closed-to-open conformational change upon interaction with Cdc42
Biochem.J., 411:485-493, 2008

PubMed Abstract: BopE is a type III secreted protein from Burkholderia pseudomallei, the aetiological agent of melioidosis, a severe emerging infection. BopE is a GEF (guanine-nucleotide-exchange factor) for the Rho GTPases Cdc42 (cell division cycle 42) and Rac1. We have determined the structure of BopE catalytic domain (amino acids 78-261) by NMR spectroscopy and it shows that BopE(78-261) comprises two three-helix bundles (alpha1alpha4alpha5 and alpha2alpha3alpha6). This fold is similar to that adopted by the BopE homologues SopE and SopE2, which are GEFs from Salmonella. Whereas the two three-helix bundles of SopE(78-240) and SopE2(69-240) form the arms of a 'Lambda' shape, BopE(78-261) adopts a more closed conformation with substantial interactions between the two three-helix bundles. We propose that arginine and proline residues are important in the conformational differences between BopE and SopE/E2. Analysis of the molecular interface in the SopE(78-240)-Cdc42 complex crystal structure indicates that, in a BopE-Cdc42 interaction, the closed conformation of BopE(78-261) would engender steric clashes with the Cdc42 switch regions. This implies that BopE(78-261) must undergo a closed-to-open conformational change in order to catalyse guanine nucleotide exchange. In an NMR titration to investigate the BopE(78-261)-Cdc42 interaction, the appearance of additional peaks per NH for residues in hinge regions of BopE(78-261) indicates that BopE(78-261) does undergo a closed-to-open conformational change in the presence of Cdc42. The conformational change hypothesis is further supported by substantial improvement of BopE(78-261) catalytic efficiency through mutations that favour an open conformation. Requirement for closed-to-open conformational change explains the 10-40-fold lower k(cat) of BopE compared with SopE and SopE2.

PubMed: 18052936
DOI: 10.1042/BJ20071546

Experimental method

SOLUTION NMR