4L4W

Structure of EspG3 chaperone from the type VII (ESX-3) secretion system

Summary for 4L4W

• Entry DOI: 10.2210/pdb4l4w/pdb
• Related: 4KXR 4RCL 5SXL
• Descriptor: EspG3 (2 entities in total)
• Functional Keywords: esx-3, type vii secretion system, rv0289, protein secretion, chaperone, pe5-ppe4, protein transport
• Biological source: Mycobacterium smegmatis
• Total number of polymer chains: 2
• Total formula weight: 64202.76

Authors

Korotkov, K.V. (deposition date: 2013-06-09, release date: 2014-06-11, Last modification date: 2023-12-06)

Primary citation

Tuukkanen, A.T.,Freire, D.,Chan, S.,Arbing, M.A.,Reed, R.W.,Evans, T.J.,Zenkeviciute, G.,Kim, J.,Kahng, S.,Sawaya, M.R.,Chaton, C.T.,Wilmanns, M.,Eisenberg, D.,Parret, A.H.A.,Korotkov, K.V.
Structural Variability of EspG Chaperones from Mycobacterial ESX-1, ESX-3, and ESX-5 Type VII Secretion Systems.
J. Mol. Biol., 431:289-307, 2019

PubMed Abstract: Type VII secretion systems (ESX) are responsible for transport of multiple proteins in mycobacteria. How different ESX systems achieve specific secretion of cognate substrates remains elusive. In the ESX systems, the cytoplasmic chaperone EspG forms complexes with heterodimeric PE-PPE substrates that are secreted from the cells or remain associated with the cell surface. Here we report the crystal structure of the EspG chaperone from the ESX-1 system determined using a fusion strategy with T4 lysozyme. EspG adopts a quasi 2-fold symmetric structure that consists of a central β-sheet and two α-helical bundles. In addition, we describe the structures of EspG chaperones from four different crystal forms. Alternate conformations of the putative PE-PPE binding site are revealed by comparison of the available EspG structures. Analysis of EspG, EspG, and EspG chaperones using small-angle X-ray scattering reveals that EspG and EspG chaperones form dimers in solution, which we observed in several of our crystal forms. Finally, we propose a model of the ESX-3 specific EspG-PE5-PPE4 complex based on the small-angle X-ray scattering analysis.

PubMed: 30419243
DOI: 10.1016/j.jmb.2018.11.003

Experimental method

X-RAY DIFFRACTION (2.036 Å)