This family consists of the GnsA/GnsB family. GnsA and GnsB are multicopy suppressors of the secG null mutation. These proteins participate in the synthesis of phospholipids, suggesting the functional relationship between SecG and membrane phospholipids. Over-expression of gnsA and gnsB causes a remarkable increase in the unsaturated fatty acid content. However, the gnsA-gnsB double null mutant exhibits no effect. Both proteins are predicted to possess a helix-turn-helix structure [1]. GnsAB is a family of putative bacterial toxins (both GnsA and GnsB) that, are neutralised by the antitoxin YmcE, Pfam:PF15939 [2].

1: Overexpression of yccL (gnsA) and ydfY (gnsB) increases levels of unsaturated fatty acids and suppresses both the temperature-sensitive fabA6 mutation and cold-sensitive secG null mutation of Escherichia coli. Sugai R, Shimizu H, Nishiyama K, Tokuda H; J Bacteriol 2001;183:5523-5528. PMID:11544213

2: Regulation of growth and death in Escherichia coli by toxin-antitoxin systems. Yamaguchi Y, Inouye M; Nat Rev Microbiol. 2011;9:779-790. PMID:21927020