9H2S

a YnaI-MscS chimera in a closed conformation purified in DDM with additional lipids showing ligand-filled pore and pockets

Summary for 9H2S

• Entry DOI: 10.2210/pdb9h2s/pdb
• EMDB information: 51817
• Descriptor: Low conductance mechanosensitive channel YnaI,Small-conductance mechanosensitive channel, DODECANE (2 entities in total)
• Functional Keywords: chimera; mechanosensitive ion channel; mscs-like, membrane protein
• Biological source: Escherichia coli (strain K12); More
• Total number of polymer chains: 7
• Total formula weight: 258718.56

Authors

Flegler, V.J.,Bottcher, B.,Rasmussen, T.,Rasmussen, A.,Hedrich, R. (deposition date: 2024-10-15, release date: 2025-09-24)

Primary citation

Flegler, V.J.,Rasmussen, A.,Hedrich, R.,Rasmussen, T.,Bottcher, B.
Mechanosensitive channel engineering: A study on the mixing and matching of YnaI and MscS sensor paddles and pores.
Nat Commun, 16:7881-7881, 2025

PubMed Abstract: Osmotically varying environments are challenging for bacterial cells. Sudden drops in osmolytes cause an increased membrane tension and rupture the cells in the absence of protective mechanisms. One family of protective proteins are mechanosensitive channels of small conductance that open in response to membrane tension. Although these channels have a common architecture, they vary widely in the number of transmembrane helices, conductivity, and gating characteristics. Although there are various structures of channels in the open and closed state, the underlying common principles of the gating mechanism remain poorly understood. Here we show that YnaI opens by radial relocation of the transmembrane sensor paddles together with a shortening of the pore, which contrasts the prototypic smaller MscS. A chimera of both channels with the YnaI sensor paddles and the pore containing C-terminal part of MscS is functional and has the tension response of the paddle donor. Our research shows that elements with different structural opening mechanisms can be mixed and matched within one channel as long as they support the common area expansion on the periplasmic side.

PubMed: 40849500
DOI: 10.1038/s41467-025-63253-0

Experimental method

ELECTRON MICROSCOPY (2.7 Å)