This is a family of bacterial proteins involved in cellulose biosynthesis. (Roemling U. and Galperin M.Y. "Bacterial cellulose biosynthesis. Diversity of operons and subunits" (manuscript in preparation)). A second component of the extracellular matrix of the multicellular morphotype (rdar) of Salmonella typhimurium and Escherichia coli is cellulose. The family does contain a P-loop sequence motif suggesting a nucleotide binding function, but this has not been confirmed.