Early biosynthetic genes

PELLETIER, M.K., MURRELL, J., SHIRLEY, B.W., Arabidopsis flavonol synthase and leucoanthocyanidin dioxygenase further evidence for distinct regulation of "early" and "late" flavonoid biosynthetic genes, Plant Physiol., 1997,113, 1437-1445. 

Moco biosynthesis is an ancient, ubiquitous, and highly conserved pathway leading to the biochemical activation of molybdenum. Mutations in the human Moco biosynthetic genes lead to death in early childhood. The affected patients show severe neurological abnormalities such as attenuated growth of the brain, seizures, and dislocated ocular lenses. So far, no effective therapy is available to cure the disease. 

Figure 4.19 Early biosynthetic pathway for thienamycin biosynthesis and assignment of functions to the different genes.

The bio genes so far identified in E. coli are represented in Figure 5. In addition to the biosynthetic genes bioABFCD, which are clustered on a divergent operon that is negatively controlled by the BirA-biotinyl-5 -AMP complex (15,16), there are three other bio genes bioR, which codes for the repressor (BirA protein) that also supports the holocarboxylase synthetase activity (see below) bioH, probably involved in early steps of the biosynthesis (17) and bioP, which codes for the specific carrier for biotin (15,18). The biotin repressor, for which a three-dimensional structure is now available, has both been studied as a model for baeterial DNA repressors and as a model for holocarboxylase synthetases (19,20). 

Fofana, B., Duguid, S., Cloutier, S., 2004. Qoning of fatty acid biosynthetic genes beta-ketoacyl CoA synthase, fatty acid elongase, stearoyl-ACP desaturase, and fatty acid desaturase and analysis of expression in the early developmental stages of flax (Unum usitatissimum L.) seeds. Plant Sci. 166, 1487-1496. 

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