In-lipid structure of pressure sensitive domains hints mechanosensitive channel functional diversity

Charalampos Kapsalis, Yue Ma, Bela E. Bode, Christos Pliotas

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
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Abstract

The mechanosensitive channel of large conductance (MscL) from Mycobacterium tuberculosis has been used as structural model for rationalizing functional observations in multiple MscL orthologues. Although these orthologues adopt similar structural architectures, they reportedly present significant functional differences. Subtle structural discrepancies on mechanosensitive channel nano-pockets are known to affect mechanical gating and may be linked to large variability in tension sensitivity among these membrane channels. Here we modify the nano-pocket regions of MscL from Escherichia coli and Mycobacterium tuberculosis and employ PELDOR/DEER distance and 3pESEEM deuterium accessibility measurements to interrogate channel structure within lipids, in which both channels adopt a closed conformation. Significant in-lipid structural differences between the two constructs suggest a more compact EcMscL at the membrane inner-leaflet, as a consequence of a rotated TM2 helix. Observed differences within lipids could explain EcMscL’s higher tension sensitivity and should be taken into account in extrapolated models used for MscL gating rationalization.
Original languageEnglish
Pages (from-to)448-459
JournalBiophysical Journal
Volume119
Issue number2
Early online date23 Jun 2020
DOIs
Publication statusPublished - 21 Jul 2020

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