Structure of a new crystal form of human Hsp70 ATPase domain

Hsp70 proteins are highly conserved proteins induced by heat shock and othe r stress conditions. An ATP-binding domain of human Hsp70 protein has been crystallized in two major morphological forms at pH 7.0 in the presence of PEG 8000 and CaCl2. Both crystal forms belong to the orthorhombic space gro up P2(1)2(1)2(1), but show no resemblance in unit-cell parameters. Analysis of the crystal structures for both forms shows a 1-2 Angstrom shift of one of the subdomains of the protein. This conformational change could reflect a 'natural' flexibility of the protein which might be relevant to ATP bind ing and may facilitate the interaction of other proteins with Hsp70 protein .