Figure 2. Structure of 3 crystallized MscS family members. Crystal structures of E. coli MscS (EcMscS), Helicobacter pylori MscS (HpMscS), and Thermoanaerobacter tengcongensis (TtMscS). Upper panel is a side view illustrating characteristic MscS family structure including a large water-filled C-terminal domain. The lower panel provides a periplasmic view of the respective channels with the residues colored in gray likely forming the vapor lock gates (EcMscS – L105 and L109, HpMscS – I94 and L98, TtMscS - L104, F108).