Browsing Pathways

Lipopolysaccharide (LPS) is a major component of outer membrane which is consisted of lipid A-core (oligosaccharide) on both inner and outer region and O-antigen (known as distal repeating unit with four sugars: N-acetylglucosamine, glucose, rhamnose and galactose). O-antigen is part of three domains of LPS, which is attached to lipid A-core; however, O-antigen and lipid A-core are synthesized separately. In this pathway, synthesis of three of O-antigen sugars is demonstrated. UDP-α-D-galactose is converted to UDP-D-Galacto-1,4-furanose by facilitation of UDP-galactopyranose mutase. dTTP glucose-1-phosphate is derivatized to dTDP-rhamnose. Fructose-6-phosphate gains an amino group, incorporates an acetate moiety and then acquires a nucleoside diphosphate resulting in UDP-N-acetyl-D-glucosamine.

Purine ribonucleoside degradation leads to the production of alpha-D-ribose-1-phosphate. Xanthosine is transported into the cytosol through a xapB. Once in the cytosol xanthosine interacts with phosphate through a xanthosine phosphorylase resulting in the release of a xanthine and a alpha-D-ribose-1-phosphate. Adenosine is transported through a nupC or a nupG transporter, once inside the cytosol it can either react with a phosphate through a adenosine phosphorylase resultin in the release of a adenine and an alpha-D-ribose-1-phosphate. Adenosine reacts with water and hydrogen ion through a adenosine deaminase resulting in the release of ammonium and inosine. Inosine reacts with phosphate through a inosine phosphorylase resulting in the release of a hypoxanthine and an alpha-D-ribose-1-phosphate. Guanosine reacts with a phosphate through a guanosine phosphorylase resulting in the release of a guanine and a alpha-D-ribose-1-phosphate.

The citrate lyase activation starts with a 3-dephospho-CoA reacting with ATP and a hydrogen ion through a triphosphoribosyl-dephospho-CoA synthase resulting in a adenine and a 2'-(5'-triphospho-alpha-D-ribosyl)-3'-dephospho-CoA. The latter compound in turn reacts with with a citrate lyase acyl-carrier protein through a apo-citrate lyase phosphoribosyl-dephospho-CoA transferase resulting in the release of a pyrophosphate and a hydrogen ion and a holo citrate lyase acyl-carrier protein.This protein complex can either react with a hydrogen ion and a acetate resulting in the release of a water and an acetyl-holo citrate lyase acyl-carrier protein. The holo acyl-carrier protein creacts with an ATP and an acetate through a citrate lyase synthase resulting in the release of an AMP, a pyrophosphate and an acetyl-holo citrate lyase acyl-ccarrier protein. The holo citrate lyase acyl-carrier protein can also interact with an S-acetyl phosphopantethiene resulting in the release of a 4-phosphopantethiene and an acetyl-holo citrate lyase acyl-carrier protein.

Guanosine can be converted into guanine through a phosphate driven guanosine phosphorylase resulting in the release of an alpha-D-ribose 1 phosphate and a guanine. This compound in turn reacts with a PRPP through a guanine phosphoribosyltransferase resulting in the release of a pyrophosphate and a GMP. Guanosine can also react with and ATP driven guanosine kinase resulting in the release of an ADP, s hydrogen ion and a GMP

Rhamnolipids (RL) consist of a fatty acyl moiety composed of a 3-(3-hydroxyalkanoyloxy)alkaloid acid (HAA) and a sugar moiety composed of one or two rhamnose sugars. Rhamnolipids function as surfactants and virulence factors and are involved in biofilm formation and cell motility. The rhamnose sugar component is produced via the dTDP-L-rhamnose biosynthetic pathway which forms dTDP-L-rhamnose from glucose 6-phosphate (G6P) in five steps. First, glucose 6-phosphate is converted into glucose 1-phosphate (G1P) via the enzyme phosphoglucomutase (AlgC). Second, glucose 1-phosphate is converted into dTDP-D-glucose via the enzyme glucose-1-phosphate thymidylyltransferase (RmlA). Third, dTDP-D-glucose is converted into dTDP-4-dehydro-6-deoxy-D-glucose via the enzyme dTDP-glucose 4,6-dehydratase (RmlB). Fourth, dTDP-4-dehydro-6-deoxy-D-glucose is converted into dTDP-4-dehydro-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose 3,5-epimerase (RmlC). Fifth, dTDP-4-dehydro-L-rhamnose is converted into dTDP-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose reductase (RmlD). The HAA component is synthesized from 3-hydroxyacyl-[acyl-carrier protein] diverted from fatty acid biosynthesis via the enzyme 3-(3-hydroxydecanoyloxy)decanoate synthase (RhIA). The final step in rhamnolipid biosynthesis is the formation of the glycosidic link between the rhamnose sugar component and the HAA component. This is accomplished by two rhamnosyltransferases (RhlB and RhlC) which catalyze sequential glycosyl transfer reactions to first form mono-rhamnolipids (via RhIB) and then di-rhamnolipids (via RhIC). RHlA, RHlB, and RHlC are associated with the inner membrane.

Rhamnolipids (RL) consist of a fatty acyl moiety composed of a 3-(3-hydroxyalkanoyloxy)alkaloid acid (HAA) and a sugar moiety composed of one or two rhamnose sugars. Rhamnolipids function as surfactants and virulence factors and are involved in biofilm formation and cell motility. The rhamnose sugar component is produced via the dTDP-L-rhamnose biosynthetic pathway which forms dTDP-L-rhamnose from glucose 6-phosphate (G6P) in five steps. First, glucose 6-phosphate is converted into glucose 1-phosphate (G1P) via the enzyme phosphoglucomutase (AlgC). Second, glucose 1-phosphate is converted into dTDP-D-glucose via the enzyme glucose-1-phosphate thymidylyltransferase (RmlA). Third, dTDP-D-glucose is converted into dTDP-4-dehydro-6-deoxy-D-glucose via the enzyme dTDP-glucose 4,6-dehydratase (RmlB). Fourth, dTDP-4-dehydro-6-deoxy-D-glucose is converted into dTDP-4-dehydro-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose 3,5-epimerase (RmlC). Fifth, dTDP-4-dehydro-L-rhamnose is converted into dTDP-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose reductase (RmlD). The HAA component is synthesized from 3-hydroxyacyl-[acyl-carrier protein] diverted from fatty acid biosynthesis via the enzyme 3-(3-hydroxydecanoyloxy)decanoate synthase (RhIA). The final step in rhamnolipid biosynthesis is the formation of the glycosidic link between the rhamnose sugar component and the HAA component. This is accomplished by two rhamnosyltransferases (RhlB and RhlC) which catalyze sequential glycosyl transfer reactions to first form mono-rhamnolipids (via RhIB) and then di-rhamnolipids (via RhIC). RHlA, RHlB, and RHlC are associated with the inner membrane.

Rhamnolipids (RL) consist of a fatty acyl moiety composed of a 3-(3-hydroxyalkanoyloxy)alkaloid acid (HAA) and a sugar moiety composed of one or two rhamnose sugars. Rhamnolipids function as surfactants and virulence factors and are involved in biofilm formation and cell motility. The rhamnose sugar component is produced via the dTDP-L-rhamnose biosynthetic pathway which forms dTDP-L-rhamnose from glucose 6-phosphate (G6P) in five steps. First, glucose 6-phosphate is converted into glucose 1-phosphate (G1P) via the enzyme phosphoglucomutase (AlgC). Second, glucose 1-phosphate is converted into dTDP-D-glucose via the enzyme glucose-1-phosphate thymidylyltransferase (RmlA). Third, dTDP-D-glucose is converted into dTDP-4-dehydro-6-deoxy-D-glucose via the enzyme dTDP-glucose 4,6-dehydratase (RmlB). Fourth, dTDP-4-dehydro-6-deoxy-D-glucose is converted into dTDP-4-dehydro-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose 3,5-epimerase (RmlC). Fifth, dTDP-4-dehydro-L-rhamnose is converted into dTDP-L-rhamnose via the enzyme dTDP-4-dehydrorhamnose reductase (RmlD). The HAA component is synthesized from 3-hydroxyacyl-[acyl-carrier protein] diverted from fatty acid biosynthesis via the enzyme 3-(3-hydroxydecanoyloxy)decanoate synthase (RhIA). The final step in rhamnolipid biosynthesis is the formation of the glycosidic link between the rhamnose sugar component and the HAA component. This is accomplished by two rhamnosyltransferases (RhlB and RhlC) which catalyze sequential glycosyl transfer reactions to first form mono-rhamnolipids (via RhIB) and then di-rhamnolipids (via RhIC). RHlA, RHlB, and RHlC are associated with the inner membrane.

The degradation of N-acetylneuraminate begins with its incorporation into the cytosol through a hydrogen symporter. Once inside the cytosol it is degraded by a N-acetylneuraminate lyase resulting in a release of a pyruvic acid and N-acetymannosamine. The latter compound is phosphorylated by an ATP driven N-Acetylmannosamine kinase resulting in the release of an ADP, a hydrogen ion and a N-Acetyl-D-mannosamine 6-phosphate. This phosphorylated compound is then metabolized by a putative N-acetylmannosamine-6-phosphate 2-epimerase resulting in the release of a N-Acetyl-D-glucosamine 6-phosphate. This compound is then deacetylated through a N-acetylglucosamine-6-phosphate deacetylase resulting in the release of an Acetic acid and a glucosamine 6-phosphate This compound can then be deaminated through a glucosamine-6-phosphate deaminase resulting in the release of an ammonium and a beta-D-fructofuranose 6-phosphate which can then be incorporated into the glycolysis pathway.

L-threonine is degrade into methylglyoxal (pyruvaldehyde) by first reacting with a NDA dependent threonine dehydrogenase resulting in the release of a hydrogen ion, an NADH and a 2-amino-3-oxobutanoate. The latter compound reacts spontaneously with a hydrogen ion resulting in the release of a carbon dioxide and a aminoacetone. The aminoacetone in turn reacts with an oxygen and a water molecule through an aminoacetone oxidase resulting in the release of a hydrogen peroxide, ammonium and a methylglyoxal which can then be incorporated in the methylglyoxal degradation pathways.

Fatty acid oxidation is also known as beta-oxidation. Fatty acids are an important energy source because they are anhydrous and can be reduced. Fatty acids are good sources of energy as they yield more energy than carbohydrates. The fatty acid oxidation pathway degrades fatty acids into acetyl-CoA under anaerobic and aerobic conditions. Enzymes of this pathway can process short and long chain fatty acids. The first step in the pathway is the conversion of acyl-CoA to enoyl-CoA. The pathway continues in a cycle, each turn removing two carbon atoms from the input acyl-CoA to produce acetyl-CoA. Each turn also produces NADH.