This family represents a novel S-layer protein widely distributed in Gammaproteobacteria including species of Pseudoalteromonas and Vibrio, and are found exclusively in marine metagenomes. These proteins assemble into paracrystalline sheets with a unique square lattice symmetry [1].

1: Slr4, a newly identified S-layer protein from marine Gammaproteobacteria, is a major biofilm matrix component. Ali S, Jenkins B, Cheng J, Lobb B, Wei X, Egan S, Charles TC, McConkey B, Austin J, Doxey AC; Mol Microbiol. 2020; [Epub ahead of print] PMID:32804439