Figure 2. Intermolecular salt bridges between the N-terminus of SLN and M4S4 of SERCA.

A) Salt bridges between SLN residues E2/E7 and SERCA residues R324/K328 are identified in crystal structure 3w5a⁶ (left) and at the end of each 1-μs MDS trajectories (right). SERCA and SLN are shown as cartoons, and residues participating in salt-bridge interactions are shown as sticks. (B). MDS distance evolution is shown between E2^SLN‒K328^SERCA, E2^SLN‒R324^SERCA, and E7^SLN‒R324^SERCA. Distances between E‒K and E‒R residue pairs were calculated between C_δ‒C_ζ and C_δ‒N_ζ atoms, respectively. The cutoff distance for salt bridge interaction using these distance definitions is 0.6 nm.³⁰