This family consists of bacterial proteins. YjgK (TabA) influences biofilm formation by toxin-antitoxin systems [1]. Another member of this family, YhcH, is a possible sugar isomerase of sialic acid catabolism [2].

1: Toxin-antitoxin systems in Escherichia coli influence biofilm formation through YjgK (TabA) and fimbriae. Kim Y, Wang X, Ma Q, Zhang XS, Wood TK; J Bacteriol. 2009;191:1258-1267. PMID:19060153

2: Crystal structure of the bacterial YhcH protein indicates a role in sialic acid catabolism. Teplyakov A, Obmolova G, Toedt J, Galperin MY, Gilliland GL; J Bacteriol. 2005;187:5520-5527. PMID:16077096