The intracellular parasite, Chlamydia, possesses a relatively small genome and lacks many of the biosynthetic pathways present in bacteria such as Escherichia coli. However, it possesses all seven genes of the common aromatic amino acid pathway which are needed to produce chorismic acid, a precursor of phenylalanine, tyrosine, tryptophan, folate, ubiquinone, and some siderophores. All but aroA are present within an operon exhibiting genes which overlap, and two of the genes are fused. Although genes of tryptophan, folate and ubiquinone biosynthesis are present, these pathways are not complete and none of the genes encoding enzymes which link chorismate to a connecting pathway of endproduct biosynthesis has been annotated. Various hypotheses are explored with respect to the functional significance of the apparent fragmented pathways; these include the existence of possible novel biochemistries, evolutionary remnants of a shrinking genome, and retention of partial pathways for modified functions. The aromatic-pathway genes are under analysis for evidence of horizontal transmission, and for their evolutionary relationship to cyanobacterial and plant genes.
What is Chorismate biosynthesis pathway for?
Is there tryptophan biosynthesis pathway in Chlamydiae?
Chlamydia genes contribute to Plant?
This analysis was prepared by Gary Xie, Roy A Jensen and Staff. Please direct questions concerning this analysis to Gary Xie.
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