9QKS

B subtilis Type VIIb Core Unit (T7bCU) + DUF

Summary for 9QKS

• Entry DOI: 10.2210/pdb9qks/pdb
• EMDB information: 53220
• Descriptor: ESX secretion system protein YukD, ESX secretion system protein YukC, ESX secretion system protein YukB,Green fluorescent protein (3 entities in total)
• Functional Keywords: t7ss, type vii secretion system, t7bcu, protein transport
• Biological source: Bacillus subtilis subsp. subtilis str. 168; More
• Total number of polymer chains: 5
• Total formula weight: 401946.33

Authors

Oka, G.U.,Fronzes, R. (deposition date: 2025-03-20, release date: 2025-11-26, Last modification date: 2025-12-03)

Primary citation

Oka, G.U.,Benoit, N.,Siroy, A.,Gubellini, F.,Marza, E.,Fronzes, R.
A ubiquitin-like protein controls assembly of a bacterial type VIIb secretion system.
Sci Adv, 11:eady9587-eady9587, 2025

PubMed Abstract: Type VII secretion systems (T7SS) are protein translocation machines crucial for virulence and bacterial competition in Gram-positive bacteria. Despite their importance, the structural basis for assembly of type VIIb secretion systems (T7SSb), a widely distributed variant in Firmicutes, remains poorly understood. We present the cryo-electron microscopy structure of the T7SSb core complex from , revealing how the ubiquitin-like protein YukD, coordinates assembly of the secretion machinery. YukD interacts extensively with the central channel component YukB and facilitates its association with the pseudokinase YukC, forming a stable building block for channel assembly. Time-lapse microscopy and competition assays demonstrate that YukD is essential for proper T7SSb complex formation and contact-dependent bacterial killing. Our findings reveal how bacteria have adapted a ubiquitin-like protein as a structural regulator for assembling a large secretion complex.

PubMed: 41270170
DOI: 10.1126/sciadv.ady9587

Experimental method

ELECTRON MICROSCOPY (3.8 Å)