Functional characterization of orchardgrass cytosolic Hsp70 (DgHsp70) and the negative regulation by Ca2+/AtCaM2 binding

► DgHsp70 confers the enhanced thermotolerance to yeast cells. ► Recombinant DgHsp70 protein played as a functional chaperone protein and an ATPase. ► DgHsp70 binds to AtCaM2 in a presence of Ca2+, and CaMBD was identified. ► Ca2+/AtCaM2 binding reduces the ATP hydrolysis of DgHsp70. ► Ca2+/AtCaM2 binding decreased foldase activity of DgHsp70.