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Core pathways operating during methylotrophy of B acillus methanolicus MGA 3 and induction of a bacillithiol‐dependent detoxification pathway upon formaldehyde stress
Author(s) -
Müller Jonas E. N.,
Meyer Fabian,
Litsanov Boris,
Kiefer Patrick,
Vorholt Julia A.
Publication year - 2015
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13200
Subject(s) - methylotroph , biology , biochemistry , cofactor , metabolic pathway , ribulose , biosynthesis , formaldehyde , oxygenase , enzyme
Summary B acillus methanolicus MGA 3 is a model facultative methylotroph of interest for fundamental research and biotechnological applications. Previous research uncovered a number of pathways potentially involved in one‐carbon substrate utilization. Here, we applied dynamic 13 C labeling to elucidate which of these pathways operate during growth on methanol and to uncover potentially new ones. B . methanolicus MGA 3 uses the assimilatory and dissimilatory ribulose monophosphate ( RuMP ) cycles for conversion of the central but toxic intermediate formaldehyde. Additionally, the operation of two cofactor‐dependent formaldehyde oxidation pathways with distinct roles was revealed. One is dependent on tri‐ and tetraglutamylated tetrahydrofolate ( THF ) and is involved in formaldehyde oxidation during growth on methanol. A second pathway was discovered that is dependent on bacillithiol, a thiol cofactor present also in other B acilli where it is known to function in redox‐homeostasis. We show that bacillithiol‐dependent formaldehyde oxidation is activated upon an upshift in formaldehyde induced by a substrate switch from mannitol to methanol. The genes and the corresponding enzymes involved in the biosynthesis of bacillithiol were identified by heterologous production of bacillithiol in E scherichia coli . The presented results indicate metabolic plasticity of the methylotroph allowing acclimation to fluctuating intracellular formaldehyde concentrations.