Cover picture: Modeling of the calcium pump from sarcoplasmic reticulum. The structure was determined at 8 Å resolution by cryoelectron microscopy and was divided up into distinct domains as shown in the surface representation of the density map (left). Helices were fitted within the transmembrane domain (cyan) and stalk (magenta). Based on a distant homology between L-2 haloacid dehalogenase, its atomic structure was fitted to the highly conserved yellow domain just above the stalk. This fitting defines a particular location for ATP (white cpk model) as well as the structural elements linking this ATP site with the calcium binding sites within the membrane. See the article by Stokes et al. on p. 1765.