Fig. 5: PIP2-binding site and possible inhibition mechanism. | Nature Communications

Fig. 5: PIP2-binding site and possible inhibition mechanism.

From: Molecular mechanism underlying regulation of Arabidopsis CLCa transporter by nucleotides and phospholipids

Fig. 5

a PI(4,5)P2 binds to the dimer interface of AtCLCa. AtCLCa-Cl− dimer is shown in side view with CBS domains hidden. Protomer A and B are shown as electrostatic potential surface model and ribbon structure, respectively. The anion and H+ transport pathways are shown as green and yellow solid surfaces, respectively. Inset: a zoom-in view of the PI(4,5)P2-binding site. PI(4,5)P2 is shown as balls and sticks. The side chain of proton glutamate Glu270 is shown as spheres. b The interaction between PI(4,5)P2 and AtCLCa-Cl−. Protomer A and B are colored in cyan and blue, respectively. Hydrogen bonds are shown as black dashed lines. c Modeled coordination of PI(3,5)P2 into the PI(4,5)P2-binding site of AtCLCa. d The C3-phosphate of PI(3,5)P2 occupies the H+ outlet. AtCLCa-Cl− is shown as a cut-open view of the electrostatic potential surface. The dashed circle indicates the H+ outlet. The C3-phosphate of PI(3,5)P2 is shown as spheres. e The C4-phosphate of PI(4,5)P2 occupies a smaller space at the H+ outlet than the C3-phosphate of PI(3,5)P2. The C4-phosphate of PI(4,5)P2 is shown as spheres.

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