Preparation of dihydroxy polycyclic aromatic hydrocarbons and activities of two dioxygenases in the phenanthrene degradative pathway.

Preparation of dihydroxy polycyclic aromatic hydrocarbons and activities of two dioxygenases in the phenanthrene degradative pathway.
Arch Biochem Biophys. 2019 Aug 21;:108081
Authors: Erwin KL, Johnson WH, Meichan AJ, Whitman CP
Abstract
Dihydroxy phenanthrene, fluoranthene, and pyrene derivatives are intermediates in the bacterial catabolism of the corresponding parent polycyclic aromatic hydrocarbon (PAH). Ring-opening of the dihydroxy species followed by a series of enzyme-catalyzed reactions generates metabolites that funnel into the Krebs Cycle with the eventual production of carbon dioxide and water. One complication in delineating these pathways and harnessing them for useful purposes is that the initial enzymatic processing produces multiple dihydroxy PAHs with multiple ring opening possibilities and products. As part of a systematic effort to address this issue, eight dihydroxy species were synthesized and characterized as the dimethoxy or diacetate derivatives. Several dihydroxy compounds were examined with two dioxygenases in the phenanthrene degradative pathway in Mycobacterium vanbaalenii PYR-1. One, 3,4-dihydroxyphenanthrene, was processed by PhdF with a kcat/Km of 6.0 × 106 M-1s-1, a value that is consistent with the annotated function of PhdF in the pathway. PhdI processed 1-hydroxy-2-naphthoate with a kcat/Km of 3.1 × 105 M-1s-1, which is also consistent with the proposed role in the pathway. The obser...

Source: Archives of Biochemistry and Biophysics - August 20, 2019 Category: Biochemistry Authors: Erwin KL, Johnson WH, Meichan AJ, Whitman CP Tags: Arch Biochem Biophys Source Type: research