Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation.
BACKGROUND: Methylobacterium extorquens AM1 is an aerobic facultative methylotrophic α-proteobacterium that can use reduced one-carbon compounds such as methanol, but also multi-carbon substrates like acetate (C₂) or succinate (C₄) as sole carbon and energy source. The organism has gained interest a...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2010-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC2948502?pdf=render |
| _version_ | 1818908359176224768 |
|---|---|
| author | Hana Smejkalová Tobias J Erb Georg Fuchs |
| author_facet | Hana Smejkalová Tobias J Erb Georg Fuchs |
| author_sort | Hana Smejkalová |
| collection | DOAJ |
| description | BACKGROUND: Methylobacterium extorquens AM1 is an aerobic facultative methylotrophic α-proteobacterium that can use reduced one-carbon compounds such as methanol, but also multi-carbon substrates like acetate (C₂) or succinate (C₄) as sole carbon and energy source. The organism has gained interest as future biotechnological production platform based on methanol as feedstock. METHODOLOGY/PRINCIPAL FINDINGS: We present a comprehensive study of all postulated enzymes for the assimilation of methanol and their regulation in response to the carbon source. Formaldehyde, which is derived from methanol oxidation, is assimilated via the serine cycle, which starts with glyoxylate and forms acetyl-CoA. Acetyl-CoA is assimilated via the proposed ethylmalonyl-CoA pathway, which thereby regenerates glyoxylate. To further the understanding of the central carbon metabolism we identified and quantified all enzymes of the pathways involved in methanol assimilation. We observed a strict differential regulation of their activity level depending on whether C₁, C₂ or C₄ compounds are used. The enzymes, which are specifically required for the utilization of the individual substrates, were several-fold up-regulated and those not required were down-regulated. The enzymes of the ethylmalonyl-CoA pathway showed specific activities, which were higher than the calculated minimal values that can account for the observed growth rate. Yet, some enzymes of the serine cycle, notably its first and last enzymes serine hydroxymethyl transferase and malate thiokinase, exhibit much lower values and probably are rate limiting during methylotrophic growth. We identified the natural C₁ carrying coenzyme as tetrahydropteroyl-tetraglutamate rather than tetrahydrofolate. CONCLUSION/SIGNIFICANCE: This study provides the first complete picture of the enzymes required for methanol assimilation, the regulation of their activity levels in response to the growth substrate, and the identification of potential growth limiting steps. |
| first_indexed | 2024-12-19T22:09:46Z |
| format | Article |
| id | doaj.art-92573d2d44c14f2cb6deb127c1a7bc36 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-19T22:09:46Z |
| publishDate | 2010-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-92573d2d44c14f2cb6deb127c1a7bc362022-12-21T20:03:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032010-01-01510e100093810.1371/journal.pone.0013001Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation.Hana SmejkalováTobias J ErbGeorg FuchsBACKGROUND: Methylobacterium extorquens AM1 is an aerobic facultative methylotrophic α-proteobacterium that can use reduced one-carbon compounds such as methanol, but also multi-carbon substrates like acetate (C₂) or succinate (C₄) as sole carbon and energy source. The organism has gained interest as future biotechnological production platform based on methanol as feedstock. METHODOLOGY/PRINCIPAL FINDINGS: We present a comprehensive study of all postulated enzymes for the assimilation of methanol and their regulation in response to the carbon source. Formaldehyde, which is derived from methanol oxidation, is assimilated via the serine cycle, which starts with glyoxylate and forms acetyl-CoA. Acetyl-CoA is assimilated via the proposed ethylmalonyl-CoA pathway, which thereby regenerates glyoxylate. To further the understanding of the central carbon metabolism we identified and quantified all enzymes of the pathways involved in methanol assimilation. We observed a strict differential regulation of their activity level depending on whether C₁, C₂ or C₄ compounds are used. The enzymes, which are specifically required for the utilization of the individual substrates, were several-fold up-regulated and those not required were down-regulated. The enzymes of the ethylmalonyl-CoA pathway showed specific activities, which were higher than the calculated minimal values that can account for the observed growth rate. Yet, some enzymes of the serine cycle, notably its first and last enzymes serine hydroxymethyl transferase and malate thiokinase, exhibit much lower values and probably are rate limiting during methylotrophic growth. We identified the natural C₁ carrying coenzyme as tetrahydropteroyl-tetraglutamate rather than tetrahydrofolate. CONCLUSION/SIGNIFICANCE: This study provides the first complete picture of the enzymes required for methanol assimilation, the regulation of their activity levels in response to the growth substrate, and the identification of potential growth limiting steps.http://europepmc.org/articles/PMC2948502?pdf=render |
| spellingShingle | Hana Smejkalová Tobias J Erb Georg Fuchs Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. PLoS ONE |
| title | Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. |
| title_full | Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. |
| title_fullStr | Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. |
| title_full_unstemmed | Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. |
| title_short | Methanol assimilation in Methylobacterium extorquens AM1: demonstration of all enzymes and their regulation. |
| title_sort | methanol assimilation in methylobacterium extorquens am1 demonstration of all enzymes and their regulation |
| url | http://europepmc.org/articles/PMC2948502?pdf=render |
| work_keys_str_mv | AT hanasmejkalova methanolassimilationinmethylobacteriumextorquensam1demonstrationofallenzymesandtheirregulation AT tobiasjerb methanolassimilationinmethylobacteriumextorquensam1demonstrationofallenzymesandtheirregulation AT georgfuchs methanolassimilationinmethylobacteriumextorquensam1demonstrationofallenzymesandtheirregulation |