Analysis of two formaldehyde oxidation pathways in Methylobacillus flagellatus KT, a ribulose monophosphate cycle methylotroph.
The roles of cyclic formaldehyde oxidation via 6-phosphogluconate dehydrogenase and linear oxidation via the tetrahydromethanopterin (H4MPT)-linked pathway were assessed in an obligate methylotroph, Methylobacillus flagellatus KT, by cloning, sequencing and mutating two chromosomal regions containing genes encoding enzymes specifically involved in these pathways: 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase and methenyl H4MPT cyclohydrolase (gndA, zwf and mch). No null mutants were obtained in gndA or zwf, implying that the cyclic oxidation of formaldehyde is required for C1 metabolism in this obligate methylotroph, probably as the main energy-generating pathway. In contrast, null mutants were generated in mch, indicating that the H4MPT-linked pathway is dispensable. These mutants showed enhanced sensitivity to formaldehyde, suggesting that this pathway plays a secondary physiological role in this methylotroph. This function is in contrast to Methylobacterium extorquens AM1, in which the H4MPT-linked pathway is essential.
Chistoserdova
Ludmila
L
Departments of Chemical Engineering1 and Microbiology2, University of Washington, Seattle, WA 98195, USA.
Gomelsky
Larissa
L
Institute of Genetics and Selection of Industrial Micro-organisms, 1st Dorozhny proezd 1, Moscow 113545, Russia4.
Vorholt
Julia A
JA
Max-Plank-Institut für Terrestrische Mikrobiologie, 35043 Marburg, Germany3.|Departments of Chemical Engineering1 and Microbiology2, University of Washington, Seattle, WA 98195, USA.
Gomelsky
Mark
M
Institute of Genetics and Selection of Industrial Micro-organisms, 1st Dorozhny proezd 1, Moscow 113545, Russia4.
Tsygankov
Yuri D
YD
Institute of Genetics and Selection of Industrial Micro-organisms, 1st Dorozhny proezd 1, Moscow 113545, Russia4.
Lidstrom
Mary E
ME
Departments of Chemical Engineering1 and Microbiology2, University of Washington, Seattle, WA 98195, USA.
D003001:Cloning, Molecular; D005557:Formaldehyde / Q000378:metabolism*; D005798:Genes, Bacterial; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D020631:Methylobacillus / Q000201:enzymology* / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D011622:Pterins / Q000378:metabolism; D012274:Ribulosephosphates / Q000378:metabolism; D017422:Sequence Analysis, DNA
D011622:Pterins; D012274:Ribulosephosphates; D005557:Formaldehyde; C042416:5,6,7,8-tetrahydromethanopterin; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase