This domain is found at the N-terminal end of Distal tail protein from Lactococcus phage p2 (Dit) and similar sequences predominantly found in Siphoviridae and bacterial prophages from Lactobacillales. Dit has a structural role and forms the distal part of the tail. It is organised into two domains, a ring domain that shows a split (this entry) barrel-like fold and a C-terminal galectin domain. Consecutive Dit N-terminal domains form a tight ring with two layers of beta-strands. This ring frames a channel sufficiently large for dsDNA passage [1,2].

1: Structure of lactococcal phage p2 baseplate and its mechanism of activation. Sciara G, Bebeacua C, Bron P, Tremblay D, Ortiz-Lombardia M, Lichiere J, van Heel M, Campanacci V, Moineau S, Cambillau C; Proc Natl Acad Sci U S A. 2010;107:6852-6857. PMID:20351260

2: Structural Insights into Lactococcal Siphophage p2 Baseplate Activation Mechanism. Spinelli S, Tremblay D, Moineau S, Cambillau C, Goulet A; Viruses. 2020; [Epub ahead of print] PMID:32796652