title: Lanthanide-Dependent Regulation of Methanol Oxidation Systems in Methylobacterium extorquens AM1 and Their Contribution to Methanol Growth.
abstract: Methylobacterium extorquens AM1 has two distinct types of methanol dehydrogenase (MeDH) enzymes that catalyze the oxidation of methanol to formaldehyde. MxaFI-MeDH requires pyrroloquinoline quinone (PQQ) and Ca in its active site, while XoxF-MeDH requires PQQ and lanthanides, such as Ce and La. Using MeDH mutant strains to conduct growth analysis and MeDH activity assays, we demonstrate that M. extorquens AM1 has at least one additional lanthanide-dependent methanol oxidation system contributing to methanol growth. Additionally, the abilities of different lanthanides to support growth were tested and strongly suggest that both XoxF and the unknown methanol oxidation system are able to use La, Ce, Pr, Nd, and, to some extent, Sm. Further, growth analysis using increasing La concentrations showed that maximum growth rate and yield were achieved at and above 1 μM La, while concentrations as low as 2.5 nM allowed growth at a reduced rate. Contrary to published data, we show that addition of exogenous lanthanides results in differential expression from the xox1 and mxa promoters, upregulating genes in the xox1 operon and repressing genes in the mxa operon. Using transcriptional reporter fusions, intermediate expression from both the mxa and xox1 promoters was detected when 50 to 100 nM La was added to the growth medium, suggesting that a condition may exist under which M. extorquens AM1 is able to utilize both enzymes simultaneously. Together, these results suggest that M. extorquens AM1 actively senses and responds to lanthanide availability, preferentially utilizing the lanthanide-dependent MeDHs when possible.
  
  
  OBJECTIVE
  The biological role of lanthanides is a nascent field of study with tremendous potential to impact many areas in biology. Our studies demonstrate that there is at least one additional lanthanide-dependent methanol oxidation system, distinct from the MxaFI and XoxF MeDHs, that may aid in classifying additional environmental organisms as methylotrophs. Further, our data suggest that M. extorquens AM1 has a mechanism to regulate which MeDH is transcribed, depending on the presence or absence of lanthanides. While the mechanism controlling differential regulation is not yet understood, further research into how methylotrophs obtain and use lanthanides will facilitate their cultivation in the laboratory and their use as a biomining and biorecycling strategy for recovery of these commercially valuable rare-earth elements.
authors.affiliation: Department of Biological Sciences, San José State University, San José, California, USA.
authors.forename: Huong N
authors.initials: HN
authors.lastname: Vu
authors.affiliation: Department of Biological Sciences, San José State University, San José, California, USA.
authors.forename: Gabriel A
authors.initials: GA
authors.lastname: Subuyuj
authors.affiliation: Department of Biological Sciences, San José State University, San José, California, USA.
authors.forename: Srividhya
authors.initials: S
authors.lastname: Vijayakumar
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA.
authors.forename: Nathan M
authors.initials: NM
authors.lastname: Good
authors.affiliation: Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA.
authors.forename: N Cecilia
authors.initials: NC
authors.lastname: Martinez-Gomez
authors.affiliation: Department of Biological Sciences, San José State University, San José, California, USA elizabeth.skovran@sjsu.edu.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Skovran
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D028581:Lanthanoid Series Elements / Q000378:metabolism*; D000432:Methanol / Q000378:metabolism*; D020601:Methylobacterium extorquens / Q000502:physiology*; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic
chemical_list: D028581:Lanthanoid Series Elements; D000429:Alcohol Oxidoreductases; C019641:alcohol dehydrogenase (acceptor); D000432:Methanol
references.citation: J Bacteriol. 1994 Jul;176(13):4052-65
references.pmid: 8021187
references.citation: PLoS One. 2010 Oct 01;5(10):null
references.pmid: 20957036
references.citation: Appl Microbiol Biotechnol. 2015 Jan;99(2):517-34
references.pmid: 25432674
references.citation: J Microbiol Biotechnol. 2014 Dec 28;24(12):1597-605
references.pmid: 25223329
references.citation: PLoS One. 2009;4(5):e5584
references.pmid: 19440302
references.citation: Biochem J. 1964 Sep;92(3):614-21
references.pmid: 4378696
references.citation: Appl Microbiol Biotechnol. 2014;98(14):6163-83
references.pmid: 24816778
references.citation: FEMS Microbiol Lett. 1998 Mar 1;160(1):119-24
references.pmid: 9495022
references.citation: PLoS One. 2013 Apr 30;8(4):e62957
references.pmid: 23646164
references.citation: Environ Sci Technol. 2013 Sep 17;47(18):10129-36
references.pmid: 23909476
references.citation: OMICS. 2007 Winter;11(4):325-40
references.pmid: 18092906
references.citation: J Bacteriol. 2003 Jan;185(2):669-73
references.pmid: 12511515
references.citation: Appl Environ Microbiol. 2015 Nov;81(21):7546-52
references.pmid: 26296730
references.citation: Science. 2015 May 22;348(6237):862-3
references.pmid: 25999492
references.citation: Environ Microbiol. 2014 Jan;16(1):255-64
references.pmid: 24034209
references.citation: J Bacteriol. 1986 May;166(2):581-90
references.pmid: 3009411
references.citation: Nat Commun. 2013;4:2785
references.pmid: 24302011
references.citation: J Bacteriol. 1984 Nov;160(2):718-23
references.pmid: 6094488
references.citation: Biotechniques. 2002 Nov;33(5):1062-7
references.pmid: 12449384
references.citation: J Bacteriol. 2011 Nov;193(21):6032-8
references.pmid: 21873495
references.citation: PLoS One. 2012;7(11):e50480
references.pmid: 23209751
references.citation: FEMS Microbiol Rev. 2010 Jul;34(4):496-531
references.pmid: 20236329
references.citation: Proc Natl Acad Sci U S A. 1979 Apr;76(4):1648-52
references.pmid: 377280
references.citation: J Biosci Bioeng. 2011 May;111(5):547-9
references.pmid: 21256798
references.citation: Microbiology. 1997 May;143 ( Pt 5):1729-36
references.pmid: 9168622
references.citation: Microbiology. 2010 Aug;156(Pt 8):2575-86
references.pmid: 20447995
references.citation: Microbiology. 1997 May;143 ( Pt 5):1737-44
references.pmid: 9168623
references.citation: Appl Environ Microbiol. 2015 Feb;81(4):1442-51
references.pmid: 25527536
references.citation: J Bacteriol. 2007 Dec;189(24):9076-81
references.pmid: 17921299
references.citation: Chemistry. 2015 Jan 19;21(4):1743-8
references.pmid: 25421364
references.citation: J Bacteriol. 2004 Jan;186(1):22-8
references.pmid: 14679220
references.citation: Environ Microbiol. 2011 Oct;13(10):2603-22
references.pmid: 21443740
references.citation: J Bacteriol. 2003 Dec;185(24):7160-8
references.pmid: 14645276
references.citation: Biomed Res Int. 2014;2014:891934
references.pmid: 24987704
references.citation: Biochem J. 1967 Sep;104(3):960-9
references.pmid: 6049934
references.citation: Appl Environ Microbiol. 2015 Mar;81(5):1775-81
references.pmid: 25548049
references.citation: Crit Rev Microbiol. 1994;20(1):13-56
references.pmid: 8185833
references.citation: Opt Express. 2015 Mar 23;23(6):7407-15
references.pmid: 25837082