HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

Benzene Ring Biosynthesis

The shikimate pathway is the common route for the biosynthesis of aromatic amino acids and most biogenic benzene derivatives in bacteria, fungi, algae, and higher plants. However, studies indicate that 3-amino-4-hydroxybenzoic acid (3,4-AHBA), a benzene derivative that serves as a precursor for several secondary metabolites including grixazone produced by Streptomyces griseus, may be derived from a non-shikimate-type pathway.

pAYP26 carrying griL and griH produces a grixazone-like pigment.

In this Paper of the Week, Hirokazu Suzuki and colleagues prove the existence of this new route from C₃ and C₄ precursors to a benzene ring. According to Suzuki et al., the pathway consists of two genes, griI and griH, that make benzene rings from the two primary metabolites, L-aspartate-4-semialdehyde and dihydroxyacetone phosphate. When expressed in Escherichia coli, the two genes caused the production of 3,4-AHBA. In vitro analysis showed that GriI catalyzes aldol condensation between the two primary metabolites to form a 7-carbon product, 2-amino-4,5-dihydroxy-6-one-heptanoic acid-7-phosphate, which is subsequently converted to 3,4-AHBA by GriH. Not only is this pathway biochemically important, but there is also considerable potential for biotechnology and metabolic engineering as the consequence of the identification of the two genes.

FOOTNOTES

See referenced article, J. Biol. Chem. 2006, 281, 36944-36951

[More Papers of the Week]