Figure 5

Structure of the L. lactis phage TP901-1 baseplate (i.e., host adsorption machinery). This figure is adapted from Veesler et al., 2012 with permission [64]. (Left) Negatively-stained electron micrograph of a TP901-1 virion. (Right) Close-up view of the phage baseplate X-ray structure fitted in the adsorption device three-dimensional electron microscopy reconstruction (the region is highlighted by a black square on the micrograph). The baseplate is formed by 18 copies of BppU (red) arranged around a central Dit hexamer (green) and holding eighteen trimeric RBPs (receptor-binding proteins, blue). The baseplate is permanently observed in the RBP downward-facing or "infection-ready" orientation.