Abstract
The S100A1 protein, involved in various physiological activities through the binding of calcium ions (Ca2+), participates in several protein-protein interaction (PPI) events after Ca2+-dependent activation. The present work investigates Ca2+-dependent conformational changes in the helix-EF hand-helix using the molecular dynamics (MD) simulation approach that facilitates the understanding of Ca2+-dependent structural and dynamic distinctions between the apo and holo forms of the protein. Furthermore, the process of ion binding by inserting Ca2+ into the bulk of the apo structure was simulated by molecular dynamics. Expectations of the simulation were demonstrated using cluster analysis and a variety of structural metrics, such as interhelical angle estimation, solvent accessible surface area, hydrogen bond analysis, and contact analysis. Ca2+ triggered a rise in the interhelical angles of S100A1 on the binding site and solvent accessible surface area. Significant configurational regulations were observed in the holo protein. The findings would contribute to understanding the molecular basis of the association of Ca2+ with the S100A1 protein, which may be an appropriate study to understand the Ca2+-mediated conformational changes in the protein target. In addition, we investigated the expression profile of S100A1 in myoblast differentiation and muscle regeneration. These data showed that S100A1 is expressed in skeletal muscles. However, the expression decreases with time during the process of myoblast differentiation.
Highlights
S100 proteins belong to the calcium ion (Ca2+ )-binding proteins family engaged in Ca2+ regulation in various tissues and organs
The initial larger root mean square deviation (RMSD) values (>0.55 nm) until ~20 ns was noted in the holo-S100A1 system
It was further observed that the domains of the S100A1 protein were significantly altered due to Ca2+ and that the alternations occurred significantly near the H3-EF site-H4 region
Summary
S100 proteins belong to the calcium ion (Ca2+ )-binding proteins family engaged in Ca2+ regulation in various tissues and organs. Many of the S100 proteins are significantly expressed in the cardiac tissue, and has been correlated with heart failure. S100A1 is adequately expressed in the cardiac muscles, skeletal muscle fibers, and brain [1]. S100A1 is especially found in the heart and in lower concentrations in the skeletal muscles in both animals and humans [2]. S100A1 expression increases progressively during cardiac development in mice and grasps a plateau in the postnatal state in the. S100A1 controls cardiac Ca2+ cycling, both the release and reuptake, and it is essential for cardiac muscle contractility and in the regulation of mitochondrial metabolism [2,4]
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