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From 2010.igem.org

ULB-Brussels developed BioBricks for production of Caulobacter crescentus glue, and won the Best New BioBrick Part, Natural award in 2009. Caulobacter crescentus is a gram-negative bacterium.

E. coli

The hfsE hfsF hfsG hfsH genes are organized in operon and their products are required for the minimum repeat unit holdfast synthesis while the polymerization of the repeat unit of the hold- fast substance needs the expression of hfsC and hfsI genes. The products of the 3 adjacent hfsD hfsA and hfsB genes are involved in the holdfast export. The anchoring of the holdfast polysaccharide is carried out by the hfa gene products.

                                 The inner membrane HfsE protein initiates glycosyltransferase by transferring

N-acetylglucosamine (NAG) from UDP−NAG to a lipid carrier. HfsG, a second glycosyltransferase protein, transfers NAG subunits to the growing polysaccharide chain. HfsH deacetylates one or more NAG residues. The HfsF protein translocates the polysaccharide chain linked to the lipid carrier across the inner membrane. The polymerases HfsC and HfsI proteins link the NAG repeat units together. The holdfast polysaccharide is transferred across the outer membrane by HfsA, HfsB and HfsD proteins. Hfa proteins mediate the polysaccharide attachment to the cell.

Our aim is to find a way of mass-producing the glue. For this purpose, we planned to transfer the C. crescentus holdfast polysaccharide biosynthesis pathway to Escherichia coli. As Escherichia coli possesses similar genes (Appendix A) involved in the production and the export of the holdfast in C. crescentus, we only inserted the hfsG and hfsH genes in an E. Coli strain : GluColi was born.

First it is possible that the similar genes found in E.coli (hfsE, hfsF, hfsC, hsfI, hfsA, hfsB and hfsD genes) do not work in an identical way than in C. crescentus. optimised for e coli