Aminosugars metabolism

The metabolic pathway of aminosugars metabolism in Cryptosporidium species is same as the pathway in Toxoplasma gondii. Cryptosporidium parvum and Cryptosporidium hominis species possess gene orthologs for all the enzymes present in T. gondii except the enzyme 2.4.1.141. The enzyme 2.3.1.4 missing in Plasmodium falciparum and T. gondii is also missing in the Cryptosporidium species. This pathway is important for the post-translational modification, N-linked glycosylation of proteins. N-linked glycosylation is the attachment of oligosaccharide chains to Asn in the tripeptide sequence Asn-X-Ser/Thr (X - any amino acid except Pro) of proteins and this facilitates the correct folding of some proteins.

 

Enzyme EC Number Gene id
Glucosamine-phosphate N-acetyltransferase 2.3.1.4 Missing in annotation
Dolichyl-diphosphooligosaccharide-protein glycotransferase 2.4.1.119 cgd2_1650
Dolichyl-diphosphooligosaccharide-protein glycotransferase 2.4.1.119 cgd6_2040
UDP-GlcNAc:dolichyl-pyrophosphoryl-GlcNAc GlcNAc transferase 2.4.1.141 Missing in annotation
Glutamine-fructose-6-phosphate transaminase 2.6.1.16 cgd1_3730
UDP-N-acetylglucosamine diphosphorylase 2.7.7.23 cgd4_810
UDP-N-acetylglucosamine-dolichyl-phosphate N-acetylglucosaminephosphotransferase 2.7.8.15 cgd5_2240
Phosphoacetylglucosamine mutase 5.4.2.3 cgd4_3310

 

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Sources and fates of metabolites

 

Substrate Source pathways Product Fate pathways
D-Fructose-6P Glycolysis    
L-glutamine Glutamate metabolism L-glutamate Glutamate metabolism
UTP Pyrimidine metabolism    
Dolichyl phosphate N-glycan biosynthesis Dolichyl pyrophosphate N-glycan biosynthesis