7JQE

Structure of an extracellular fragment of EsaA from Streptococcus gallolyticus

Summary for 7JQE

• Entry DOI: 10.2210/pdb7jqe/pdb
• Descriptor: ESAT-6/WXG100 secretion system protein, CHLORIDE ION, 1,2-ETHANEDIOL, ... (4 entities in total)
• Functional Keywords: bacterial type vii secretion system, bacterial toxin transport, membrane protein, protein transport
• Biological source: Streptococcus gallolyticus (strain ATCC 43143 / F-1867)
• Total number of polymer chains: 1
• Total formula weight: 67530.64

Authors

Klein, T.A.,Grebenc, D.W.,Kim, Y.,Whitney, J.C. (deposition date: 2020-08-10, release date: 2020-11-11, Last modification date: 2024-10-23)

Primary citation

Klein, T.A.,Grebenc, D.W.,Gandhi, S.Y.,Shah, V.S.,Kim, Y.,Whitney, J.C.
Structure of the Extracellular Region of the Bacterial Type VIIb Secretion System Subunit EsaA.
Structure, 29:177-185.e6, 2021

PubMed Abstract: Gram-positive bacteria use type VII secretion systems (T7SSs) to export effector proteins that manipulate the physiology of nearby prokaryotic and eukaryotic cells. Several mycobacterial T7SSs have established roles in virulence. By contrast, the genetically distinct T7SSb pathway found in Firmicutes bacteria more often functions to mediate bacterial competition. A lack of structural information on the T7SSb has limited the understanding of effector export by this protein secretion apparatus. Here, we present the 2.4 Å crystal structure of the extracellular region of the T7SSb subunit EsaA from Streptococcus gallolyticus. Our structure reveals that homodimeric EsaA is an elongated, arrow-shaped protein with a surface-accessible "tip", which in some species of bacteria serves as a receptor for lytic bacteriophages. Because it is the only T7SSb subunit large enough to traverse the peptidoglycan layer of Firmicutes, we propose that EsaA plays a critical role in transporting effectors across the entirety of the Gram-positive cell envelope.

PubMed: 33238147
DOI: 10.1016/j.str.2020.11.002

Experimental method

X-RAY DIFFRACTION (2.4 Å)