YjbH is a family of Gram-negative beta-barrel outer-membrane lipoproteins that act as putative porins. YbjH is one of four gene-products expressed from an operon, yjbEFGH, which is regulated by the Rcs phosphorelay in a RcsA-dependent manner, similar to that of other exopolysaccharide biosynthetic pathways. It is highly possible that the yjbEFGH operon encodes a system involved in EPS secretion since none of the products is predicted to have enzymic activity, the products are all secreted and YbjH and F are predicted to be beta-barrel lipoproteins similar to porins. It may be that the operon products play some role in biofilm formation and/or matrix production [1].

1: The yjbEFGH locus in Escherichia coli K-12 is an operon encoding proteins involved in exopolysaccharide production. Ferrieres L, Aslam SN, Cooper RM, Clarke DJ; Microbiology. 2007;153:1070-1080. PMID:17379715

2: Crystal structure of E. coli group 4 capsule protein GfcC reveals a domain organization resembling Wza. Sathiyamoorthy K, Mills E, Franzmann TM, Rosenshine I, Saper MA; Biochemistry 2011;0:0-0. PMID:21449614