154

Calcium Biochemistry

Fig. 3

Ribbon structure of human m-calpain in the absence of calcium. The 80 kDa large

subunit starts in the molecular center, folds into the surface of the dIIa subdomain, forms the

catalytic domain dII, builds domain dIII, runs down, and forms the right-side calmodulin-like

domain dIV. The 30 kDa small subunit becomes visible before forming the left-side calmodulin

domain dVI. (Reprinted with permission from Strobl et al., 2000,

Proc. Natl. Acad. Sci. USA

,

97

,

588–592.)