The crystal structure of the "heads-down" conformations of L. lactis phage p2 baseplate. (A) Side view in ribbon representation of the "heads-down" conformations of L. lactis phage p2 baseplate. (B) View from top (ORF15, green; ORF16, pink; ORF18 (RBP), blue). (C) Superposition of the rings formed by the N-terminal domains of ORF15. ORF18 (RBP) trimers have undergone a 200° rotation downwards . This figure has been taken from Sciara et al., 2010 with permission .