Table 2 Comparison of essential metabolic pathways among Cryptosporidium spp. and some other common apicomplexan parasites
Category | Metabolic pathway | Cchi | Cpar | Chom | Cmel | Cubi | Cbai | Cand | Pfal | Tgon |
|---|---|---|---|---|---|---|---|---|---|---|
Carbohydrate and energy metabolism | Glycolysis | + | + | + | + | + | + | + | + | + |
Methylcitrate cycle | – | – | – | – | – | – | – | – | + | |
TCA cycle | – | – | – | – | – | – | + | + | + | |
Pentose phosphate pathway | – | – | – | – | – | – | – | + | + | |
Shikimate biosynthesis | – | – | – | – | – | – | – | + | + | |
Folate biosynthesis | – | – | – | – | – | – | – | + | + | |
Synthesis of pterin | – | – | – | – | – | – | – | – | + | |
Galactose metabolism | – | – | – | – | – | – | – | – | + | |
Synthesis of starch | + | + | + | + | + | + | + | – | + | |
Synthesis of trehalose | + | + | + | + | + | + | + | – | + | |
Synthesis of 1,3-beta-glucan | – | – | – | – | – | – | – | – | + | |
Conversion between UDP-Glc and UDP-Gal | + | + | + | + | + | + | + | – | + | |
Conversion between GDP-Man and GDP-Fuc | – | – | – | – | – | – | – | + | + | |
Conversion from UDP-Glc to UDP-GlcA to UDP-Xyl | + | + | + | + | + | + | + | – | – | |
Synthesis of mannitol from fructose | + | + | + | + | + | + | + | – | – | |
Fatty acid biosynthesis in cytosol (FAS I) | + | + | + | + | + | + | + | – | + | |
Fatty acid biosynthesis in apicoplast (FAS II) | – | – | – | – | – | – | – | + | + | |
Fatty acid degradation | – | – | – | – | – | – | – | – | + | |
Oxidative phosphorylation (NADH dehydrogenase) | + | + | + | + | + | + | + | + | + | |
Oxidative phosphorylation (Complex II) | – | – | – | – | – | – | + | + | + | |
Oxidative phosphorylation (Complex III) | – | – | – | – | – | – | 1 sub | + | + | |
Oxidative phosphorylation (Complex IV) | – | – | – | – | – | – | – | + | + | |
F-ATPase | 2 sub | 2 sub | 2 sub | 2 sub | 2 sub | 2 sub | + | + | + | |
Alternative oxidase (AOX) | + | + | + | + | – | – | + | – | – | |
Glyoxalase metabolism producing D-lactate | – | – | – | – | – | – | – | + | + | |
Synthesis of isoprene (MEP/DOXP) | – | – | – | – | – | – | – | + | + | |
Synthesis of farnesyl/polyprenyl diphosphate | + | + | + | + | – | – | + | + | + | |
Nucleotide metabolism | Synthesis of purine rings de novo | – | – | – | – | – | – | – | – | – |
Conversion from IMP to XMP | + | + | + | + | + | – | – | + | + | |
Conversion from XMP to GMP | – | + | + | – | – | – | – | + | + | |
Synthesis of pyrimidine de novo | – | – | – | – | – | – | – | + | + | |
Amino acid metabolism | Synthesis of alanine from pyruvate | – | – | – | – | – | – | – | – | + |
Synthesis of glutamate from nitrite/nitrate | – | – | – | – | – | – | – | + | + | |
Conversion from glutamate to glutamine | + | + | + | + | + | + | + | + | + | |
Synthesis of aspartate from oxaloacetate and glutamate | – | – | – | – | – | – | – | + | + | |
Conversion from aspartate to asparagine | + | + | + | + | + | – | – | + | + | |
Conversion from glutamate to proline | + | + | + | + | + | + | + | – | + | |
Synthesis of serine from glycerate/glycerol phosphate | – | – | – | – | – | – | – | – | + | |
Conversion from serine to cysteine | – | – | – | – | – | – | – | – | + | |
Conversion from serine to glycine | + | + | + | + | + | + | + | + | + | |
Recycle homocysteine into methionine | – | – | – | – | – | – | – | + | + | |
Synthesis of lysine from aspartate | – | – | – | – | – | – | – | – | + | |
Synthesis of threonine from aspartate | – | – | – | – | – | – | – | – | + | |
Synthesis of ornithine from arginine | – | – | – | – | – | – | – | + | – | |
Synthesis of ornithine from proline | – | – | – | – | – | – | – | + | + | |
Synthesis of polyamine from ornithine | – | – | – | – | – | – | – | + | – | |
Polyamine pathway backward | + | + | + | + | + | + | + | – | + | |
Degradation of branch-chain amino acids | – | – | – | – | – | – | – | – | + | |
Synthesis of tryptophan | + | + | + | – | + | – | – | – | – | |
Aromatic amino acid hydroxylases (AAAH) | – | – | – | – | – | – | – | – | + | |
Vitamin and others | Synthesis of ubiquinone (Coenzyme Q) | + | + | + | + | – | – | + | + | + |
Synthesis of Fe-S cluster | + | + | + | + | + | + | + | + | + | |
Synthesis of heme | – | – | – | – | – | – | – | + | + | |
Synthesis of thiamine (Vitamin B1) | – | – | – | – | – | – | – | + | – | |
Conversion from thiamine to thiamine pyrophosphate (TPP) | – | – | – | – | – | – | – | + | + | |
Synthesis of FMN/FAD from riboflavin | – | – | – | – | – | – | – | + | + | |
Synthesis of pyridoxal phosphate (Vitamin B6) de novo | – | – | – | – | – | – | – | + | + | |
Synthesis of NAD(P) + de novo from nicotinate/nicotinamide | – | – | – | – | – | – | – | + | + | |
Synthesis of pantothenate from valine | – | – | – | – | – | – | – | – | + | |
Synthesis of CoA from pantothenate | + | + | + | + | + | + | + | + | + | |
Synthesis of lipoic acid de novo in apicoplast | – | – | – | – | – | – | – | + | + | |
Salvage of lipoic acid in mitochondria | – | – | – | – | – | – | + | + | + | |
Synthesis of porphyrin/cytochrome proteins | – | – | – | – | – | – | – | + | + |