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5vba

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Structure of EspG1 chaperone from the type VII (ESX-1) secretion system determined with the assistance of N-terminal T4 lysozyme fusion

Structural highlights

5vba is a 2 chain structure with sequence from Escherichia virus T4 and Mycobacterium kansasii ATCC 12478. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.27Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

X7YCN8_MYCKA ENLYS_BPT4 Endolysin with lysozyme activity that degrades host peptidoglycans and participates with the holin and spanin proteins in the sequential events which lead to the programmed host cell lysis releasing the mature viral particles. Once the holin has permeabilized the host cell membrane, the endolysin can reach the periplasm and break down the peptidoglycan layer.^[1]

Publication Abstract from PubMed

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 EspG1 chaperone from the ESX-1 system determined using a fusion strategy with T4 lysozyme. EspG1 adopts a quasi 2-fold symmetric structure that consists of a central beta-sheet and two alpha-helical bundles. Additionally, we describe the structures of EspG3 chaperones from four different crystal forms. Alternate conformations of the putative PE-PPE binding site are revealed by comparison of the available EspG3 structures. Analysis of EspG1, EspG3 and EspG5 chaperones using small-angle X-ray scattering (SAXS) reveals that EspG1 and EspG3 chaperones form dimers in solution, which we observed in several of our crystal forms. Finally, we propose a model of the ESX-3 specific EspG3-PE5-PPE4 complex based on the SAXS analysis.

Structural Variability of EspG Chaperones from Mycobacterial ESX-1, ESX-3 and ESX-5 Type VII Secretion Systems.,Tuukkanen AT, Freire D, Chan S, Arbing MA, Reed RW, Evans TJ, Zenkeviciute G, Kim J, Kahng S, Sawaya MR, Chaton CT, Wilmanns M, Eisenberg D, Parret AHA, Korotkov KV J Mol Biol. 2018 Nov 9. pii: S0022-2836(18)30423-6. doi:, 10.1016/j.jmb.2018.11.003. PMID:30419243^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Moussa SH, Kuznetsov V, Tran TA, Sacchettini JC, Young R. Protein determinants of phage T4 lysis inhibition. Protein Sci. 2012 Apr;21(4):571-82. doi: 10.1002/pro.2042. Epub 2012 Mar 2. PMID:22389108 doi:http://dx.doi.org/10.1002/pro.2042
↑ Tuukkanen AT, Freire D, Chan S, Arbing MA, Reed RW, Evans TJ, Zenkeviciute G, Kim J, Kahng S, Sawaya MR, Chaton CT, Wilmanns M, Eisenberg D, Parret AHA, Korotkov KV. Structural Variability of EspG Chaperones from Mycobacterial ESX-1, ESX-3 and ESX-5 Type VII Secretion Systems. J Mol Biol. 2018 Nov 9. pii: S0022-2836(18)30423-6. doi:, 10.1016/j.jmb.2018.11.003. PMID:30419243 doi:http://dx.doi.org/10.1016/j.jmb.2018.11.003