Fig. 8: Interactions between SecR and Gs protein during MD simulations.

a Hydrogen bonds between SecR and Gs protein. The total occupancy (% frames) of each atom is plotted onto the equilibrated complex according to a color scale, with SecR atoms never involved in white, G protein (Gα subunit) never involved in orange, and G protein (Gβ subunit) never involved in cyan; atoms highly involved are magenta. The Gγ subunit is shown as green ribbon, the Gα subunit (ball and stick residues indicated with solid lines) is depicted in orange, partially transparent ribbon, the Gβ subunit (ball and stick residues indicated with solid lines) is shown as cyan, partially transparent ribbon; the SecR (stick residues indicated with dashed lines) is shown as white partially transparent ribbon. The image on the right specifies the relative perspectives from the left and right sides. View from left side) View from the TM6/TM7/TM8 side; View from right side) View from the TM1/TM2/TM3 side. Main hydrogen bonds involved SecR ICL1 (R169^ICL1), TM5 (K323^5.64) ICL3 (E328^ICL3, R330^ICL3, T326^ICL3, and R325^ICL3), TM6 (R339^6.37 and R342^6.40), and H8 (K401^8.56). On the G protein, the α subunit residues L394, Y391, R385, Q384, D381, R342, D343, and Q35 were highly involved; the only β subunit side-chain engaged was D312. b Contacts between SecR and Gs protein. The total occupancy (% frames) of each atom is plotted onto the surface of the equilibrated complex according to a color scale, with atoms never involved in blue, and atoms highly involved in red. The central image specifies the relative perspectives from above and below. View from above) Contacts plotted on the G protein surface (the bottom figure shows the ribbon representation as reference). Main interactions involved D312 (Gβ subunit), L394, E392, L393, Y391, H387, R385, Q384, R380, R342, R38 (Gα subunit). View from below) Contacts plotted on the SecR surface (the bottom figure shows the ribbon representation as reference). Main interactions involved ICL1 (R169^ICL1), TM2 (R174^2.46), ICL2 (F248^ICL2), TM3 (L243^3.57 and L244^3.58), TM5 (K323^5.64), ICL3 (E328^ICL3 and R330^ICL3), TM6 (R339^6.37 and R342^6.40), and H8 (K401^8.56).