Abstract
In the methylotrophic bacterium Methylobacterium extorquens strain AM1, MxaF, a Ca2+-dependent methanol dehydrogenase (MDH), is the main enzyme catalyzing methanol oxidation during growth on methanol. The genome of strain AM1 contains another MDH gene homologue, xoxF1, whose function in methanol metabolism has remained unclear. In this work, we show that XoxF1 also functions as an MDH and is La3+-dependent. Despite the absence of Ca2+ in the medium strain AM1 was able to grow on methanol in the presence of La3+. Addition of La3+ increased MDH activity but the addition had no effect on mxaF or xoxF1 expression level. We purified MDH from strain AM1 grown on methanol in the presence of La3+, and its N-terminal amino acid sequence corresponded to that of XoxF1. The enzyme contained La3+ as a cofactor. The ΔmxaF mutant strain could not grow on methanol in the presence of Ca2+, but was able to grow after supplementation with La3+. Taken together, these results show that XoxF1 participates in methanol metabolism as a La3+-dependent MDH in strain AM1.
Highlights
Methylotrophs are microorganisms with the ability to utilize reduced C1-compounds, such as methane, methanol and methylamine as their sole carbon and energy source
We showed that lanthanum (La), cerium (Ce), and praseodymium (Pr), all of which are belong to the rare earth elements (REE), increased methanol dehydrogenase (MDH) activity in cell extracts of M. radiotolerans and the non-methylotrophic bacteria Bradyrhizobium sp. [23,24]
We showed that some REEs increased MDH activity in M. radiotolerans and the non-methylotrophic Bradyrhizobium sp. [23,24]
Summary
Methylotrophs are microorganisms with the ability to utilize reduced C1-compounds, such as methane, methanol and methylamine as their sole carbon and energy source. They are ubiquitous in nature, and some of them are well-known plant epiphytes [1,2]. In the methylotrophic metabolism of Methylobacterium, methanol is first oxidized to formaldehyde via methanol dehydrogenase (MDH) in the periplasm [13,14]. MxaF and MxaI are encoded by mxaFI genes located in the large mxa gene cluster [17], and both are essential for growth on methanol, as the loss of these genes in strain AM1 eliminates virtually all methanol dehydrogenase activity [18,19]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
