Metabolic Diversity for Degradation, Detection, and Synthesis of Nitro Compounds and Toxins

Abstract : The biosynthesis and biodegradation of natural products may be the source of many of the unknown and hypothetical genes being revealed by genomics and metagenomics. The biodegradation pathways of a range of naturally occurring compounds structurally related to compounds of interest to DoD were elucidated along with the genes and enzymes responsible for the catabolic reactions. The purpose was to explore the metabolic diversity of catabolic pathways for natural compounds as the potential source of genetic content that has led to the recent, rapid evolution of pathways for degradation of synthetic chemicals. Bacteria were isolated that are able to grow on the natural nitro compounds 3-nitrotyrosine, 3-nitropropionic acid, 1-nitro-2-phenylethane, diphenylamine, 5-nitroanthranilic acid, 2-nitroimidazole, chloramphenicol, N-nitroethylenediamine, 8-nitroguanine, and a natural organophosphate, (S)-cinnamoylphosphoramide. Other isolates were able to grow on the synthetic compounds nitroglycerin, 2,4-dinitroanisole, and 4-nitroaniline. In some cases new enzymes and enzyme functions were discovered, in one system the long-standing mystery of the physiological substrate of the enzyme encoded by a widespread gene was settled. Although only a limited sample of natural compounds was studied, the results indicated that catabolic pathways for natural oganic compounds comprise a previously untapped source of metabolic diversity with the potential for wide applications in biocatalysis for materials synthesis and destruction.