Electrostatic interactions between single arginine and phospholipids modulate physiological properties of sarcoplasmic reticulum Ca²⁺-ATPase.

ABSTRACT: Arg324 of sarcoplasmic reticulum Ca²⁺-ATPase forms electrostatic interactions with the phosphate moiety of phospholipids in most reaction states, and a hydrogen bond with Tyr122 in other states. Using site-directed mutagenesis, we explored the functional roles of Arg324 interactions, especially those with lipids, which at first glance might seem too weak to modulate the function of such a large membrane protein. The hydrogen bond forms transiently and facilitates Ca²⁺ binding from the cytoplasmic side. The contributions of the electrostatic interactions to the reaction steps were quantified using a rate vs activity coefficient plot. We found that the interaction between Arg324 and lipids decreases the affinity for luminal Ca²⁺. The transformation rate of th

SUBMITTER: Yamasaki K 

PROVIDER: S-EPMC9288429 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature