7CU9

Crystal structure of the soluble domain of TiME protein from Mycobacterium smegmatis

Summary for 7CU9

• Entry DOI: 10.2210/pdb7cu9/pdb
• Descriptor: Tube-forming protein in Mycobacterial Envelpe, TiME, MAGNESIUM ION, GLYCEROL, ... (4 entities in total)
• Functional Keywords: tubular protein, envelope-spanning channel, protein transport, potential drug target
• Biological source: Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155)
• Total number of polymer chains: 2
• Total formula weight: 42363.14

Authors

Gong, W.,Cai, X.,Liu, L.,Wen, C. (deposition date: 2020-08-21, release date: 2021-08-25, Last modification date: 2024-10-16)

Primary citation

Cai, X.,Liu, L.,Qiu, C.,Wen, C.,He, Y.,Cui, Y.,Li, S.,Zhang, X.,Zhang, L.,Tian, C.,Bi, L.,Zhou, Z.H.,Gong, W.
Identification and architecture of a putative secretion tube across mycobacterial outer envelope.
Sci Adv, 7:-, 2021

PubMed Abstract: Tuberculosis-causing mycobacteria have thick cell-wall and capsule layers that are formed from complex structures. Protein secretion across these barriers depends on a specialized protein secretion system, but none has been reported. We show that Rv3705c and its homologous MSMEG_6251 in are tube-forming proteins in the mycobacterial envelope (TiME). Crystallographic and cryo-EM structures of these two proteins show that both proteins form rotationally symmetric rings. Two layers of TiME rings pack together in a tail-to-tail manner into a ring-shaped complex, which, in turn, stacks together to form tubes. TiME was detected mainly in the cell wall and capsule. Knocking out the TiME gene markedly decreased the amount of secreted protein in the culture medium, and expression of this gene in knocked-out strain partially restored the level of secreted protein. Our structure and functional data thus suggest that TiME forms a protein transport tube across the mycobacterial outer envelope.

PubMed: 34417177
DOI: 10.1126/sciadv.abg5656

Experimental method

X-RAY DIFFRACTION (1.55 Å)