June 2010 issue
Cover illustration: Tetrameric arrangement of a subdomain of the InvA cytoplasmic region of Salmonella (p. 709). InvA is a core element of the protein type III secretion system, and consists of a transmembrane N-terminal domain and a soluble cytoplasmic domain. The crystal structure of roughly half the cytoplasmic domain of Salmonella InvA reveals that it contains a repeating fold found in many elements of the type III secretion system `molecular syringe'. In addition, this domain forms a crystallographic tetramer (shown with each chain a different color) that buries roughly 10 000 Å2 of surface area.