Biosynthesis of human milk oligosaccharides in engineered bacteria
The invention provides compositions and methods for engineering bacteria to produce fucosylated oligosaccharides, and the use thereof in the prevention or treatment of infection.
1. An isolated E. coli bacterium comprising
(i) an exogenous β-galactosidase encoded by an engineered β-galactosidase gene insert, said E. coli comprising a detectable level of β-galactosidase activity that is reduced compared to that of a wild-type E. coli bacterium, wherein the level of β-galactosidase activity comprises between 0.05 and 200 units;
(ii) an inactivating mutation in a colanic acid synthesis gene;
(iii) an exogenous fucosyltransferase gene; and
(iv) a functional lactose permease gene,
wherein the endogenous LacZ gene of said E. coli is deleted or functionally inactivated.
2. The bacterium of claim 1 , wherein said colanic acid synthesis gene comprises an E. coli wcaJ, wzxC, wcaD, wza, wzb, or wzc gene.
3. The bacterium of claim 2 , wherein said colanic acid synthesis gene comprises a wcaJ gene.
4. The bacterium of claim 1 , comprising an increased intracellular guanosine diphosphate (GDP)-fucose level, wherein the increased intracellular GDP-fucose level is at least 10% more than the level of GDP-fucose in a wild-type bacterium.
5. The bacterium of claim 1 , wherein said exogenous fucosyltransferase gene encodes α(1,2) fucosyltransferase and/or α(1,3) fucosyltransferase.
6. The bacterium of claim 5 , wherein said α(1,2) fucosyltransferase gene comprises a Bacteroides fragilis wcfW gene.
7. The bacterium of claim 5 , wherein said α(1,2) fucosyltransferase gene comprises a Helicobacter pylori 26695 futC gene.
8. The bacterium of claim 1 , wherein said α(1,3) fucosyltransferase gene comprises a Helicobacter pylori 26695 futA gene.
9. The bacterium of claim 1 , wherein said lactose permease gene is an endogenous lactose permease gene.
10. The bacterium of claim 1 , wherein said lactose permease gene comprises an E. coli lacY gene.
11. The bacterium of claim 1 , further comprising an exogenous E. coli rcsA or E. coli rcsB gene.
12. The bacterium of claim 1 , further comprising an inactivating mutation in a lacA gene.
13. The bacterium of claim 1 , further comprising an exogenous sialyltransferase gene.
14. The bacterium of claim 13 , wherein said exogenous sialyltransferase gene encodes an α(2,3)sialyl transferase.
15. The bacterium of claim 1 , further comprising a deficient sialic acid catabolic pathway comprising a null mutation in an endogenous N-acetylneuraminate lyase gene or a null mutation in an endogenous N-acetylmannosamine kinase gene.
16. The bacterium of claim 1 , further comprising an inactivating mutation in a ion gene.
17. The bacterium of claim 1 , comprising an increased intracellular lactose level, wherein the increased intracellular lactose level is at least 10% more than the level in a wild-type bacterium.
18. The bacterium of claim 1 , wherein the level of β-galactosidase activity comprises between 0.05 and 5 units.
19. The bacterium of claim 1 , wherein the level of β-galactosidase activity comprises between 0.05 and 4 units.
20. The bacterium of claim 1 , wherein the level of β-galactosidase activity comprises between 0.05 and 3 units.
21. The bacterium of claim 1 , wherein the level of β-galactosidase activity comprises between 0.05 and 2 units.
22. The bacterium of claim 1 , wherein said lactose permease gene is an exogenous lactose permease gene.