AiM  Vol.3 No.6 A , October 2013
Molybdenum Limitation Induces Expression of the Molybdate-Binding Protein Mop in a Freshwater Nitrogen-Fixing Cyanobacterium

We studied the effect of molybdenum (Mo) concentration on transcription and translation of a putative Mo-storage protein (Mop) in the freshwater heterocystous cyanobacterium, Nostoc sp. PCC 7120. Triplicate treatments were acclimated to 1, 150, and 3000 nM Mo over an 11-day period (three transfers) and then transferred into 3000 nM Mo media. Growth rates in 1 nM treatments declined throughout the acclimation period and increased significantly after the final transfer into media containing 3000 nM Mo. After acclimation, cellular Mo content was highest in 3000 nM Mo treatments, intermediate in 150 nM treatments and lowest in 1 nM treatments (70 ± 30, 10.0 ± 0.04 and 2 ± 1 mg·gˉ1 dry biomass, respectively). Cellular Mo content converged on values of 20-40 mg·1 dry biomass after the final transfer into 3000 nM. Mop transcription and translation were up-regulated in 1 nM Mo treatments during the acclimation period, and down-regulated after transfer into 3000 nM Mo. Mop protein expression was only observed in 1 nM treatments after multiple transfers; minimal Mop protein was observed in 150 and 3000 nM Mo treatments. These observations suggest that Mop does not store excess intracellular Mo in Nostoc sp. PCC 7120, but may serve an unknown physiological function in Mo-limited metabolism.


Cite this paper
J. Glass, A. Poret-Peterson, F. Wolfe-Simon and A. Anbar, "Molybdenum Limitation Induces Expression of the Molybdate-Binding Protein Mop in a Freshwater Nitrogen-Fixing Cyanobacterium," Advances in Microbiology, Vol. 3 No. 6, 2013, pp. 9-15. doi: 10.4236/aim.2013.36A002.
[1]   J. B. Glass, R. P. Axler, S. Chandra, S. and C. R. Goldman, “Molybdenum Limitation of Microbial Nitrogen Assimilation in Aquatic Ecosystems and Pure Cultures,” Frontiers in Microbiology, Vol. 3, No. 331, 2012.

[2]   Y. Zhang and V. N. Gladyshev, “Molybdoproteomes and Evolution of Molybdenum Utilization,” Journal of Molecular Biology, Vol. 379, No. 4, 2008, pp. 881-899.

[3]   R. W. Collier, “Molybdenum in the Northeast Pacific Ocean,” Limnology and Oceangraphy, Vol. 30, No. 6, 1985, pp. 1351-1354.

[4]   R. W. Howarth, R. Marino and J. J. Cole, “Nitrogen Fixation in Freshwater, Estuarine, and Marine Ecosystems. 2. Biogeochemical Controls,” Limnology and Oceangraphy, Vol. 33, No. 4, 1988, pp. 688-701.

[5]   A. R. Barron, N. Wurzburger, J. P. Bellenger, S. J. Wright, A. M. L. Kraepiel and L. O. Hedin, “Molybdenum Limitation of Asymbiotic Nitrogen Fixation in Tropical Forest Soils,” Nature Geoscience, Vol. 2, No. 1, 2009, pp. 42-45.

[6]   W. B. Silvester, “Molybdenum Limitation of Asymbiotic nitrogen Fixation in Forests of Pacific Northwest America,” Soil Biology and Biochemistry, Vol. 21, No. 2, 1989, pp. 283-289.

[7]   I. C. Romero, N. J. Klein, S. A. Sanudo-Wilhelmy and D. G. Capone, “Potential Trace Metal Co-Limitation Controls on N2 Fixation and NO3-Uptake in Lakes with Varying Trophic Status,” Frontiers in Microbiology, Vol. 4, No. 54, 2013.

[8]   R. P. Axler, R. M. Gersberg and C. R. Goldman, “Stimulation of Nitrate Uptake and Photosynthesis by Molybdenum in Castle Lake, California,” Canadian Journal of Fisheries and Aquatic Science, Vol. 37, No. 4, 1980, pp. 707-712.

[9]   W. T. Self, A. M. Grunden, A. Hasona and K. T. Shanmugam, “Molybdate Transport,” Research in Microbiology, Vol. 152, No. 3-4, 2001, pp. 311-321.

[10]   R. N. Pau, “Molybdenum Uptake and Homeostasis,” In: W. Klipp, B. Masepohl, J. R. Gallon and W. E. Newton, Eds., Genetics and Regulation of Nitrogen Fixation in Free-Living Bacteria, Vol. 2, Springer, Dordrecht, 2004, pp. 225-256.

[11]   J. P. Bellenger, T. Wichard, T., A. B. Kustka and A. M. Kraepiel, “Uptake of Molybdenum and Vanadium by a Nitrogen-Fixing Soil Bacterium Using Siderophores,” Nature Geoscience, Vol. 1, No. 4, 2008, pp. 243-246.

[12]   L. J. Liermann, R. L. Guynn, A. D. Anbar and S. L. Brantley, “Production of a Molybdophore during Metal-Tar-geted Dissolution of Silicates by Soil Bacteria,” Chemical Geology, Vol. 220, No. 3-4, 2005, pp. 285-302.

[13]   J. P. Bellenger, T. Wichard, Y. Xu and A. M. L. Kraepiel, “Essential Metals for Nitrogen Fixation in a Free Living N2 Fixing Bacterium: Chelation, Homeostasis and High Use Efficiency,” Environmental Microbiology, Vol. 13, No. 6, 2011, pp. 1395-1411.

[14]   R. R. Eady, “Structure-Function Relationships of Alternative Nitrogenases,” Chemical Reviews, Vol. 96, No. 7, 1996, pp. 3013-3030.

[15]   D. Fenske, et al., “A New Type of Metalloprotein: The Mo Storage Protein from Azotobacter vinelandii Contains a Polynuclear Molybdenum-Oxide Cluster,” ChemBio-Chem, Vol. 6, No. 2, 2005, pp. 405-413.

[16]   J. Schemberg, K. Schneider, D. Fenske and A. Müller, “Azotobacter vinelandii Metal Storage Protein: ‘Classical’ Inorganic Chemistry Involved in Mo/W Uptake and Release Processes,” ChemBioChem, Vol. 9, No. 4, 2008, pp. 595-602.

[17]   S. M. Hinton and B. Merritt, “Purification and Characterization of a Molybdenum-Pterin-Binding Protein (Mop) in Clostridium pasteurianum W5,” Journal of Bacteriology, Vol. 168, No. 2, 1986, pp. 688-693.

[18]   S. M. Hinton and G. Freyer, “Cloning, Expression and Sequencing the Molybdenum-Pterin Binding Protein (mop) Gene of Clostridium pasteurianum in Escherichia coli,” Nucleic Acids Research, Vol. 14, No. 23, 1986, pp. 9371-9380.

[19]   S. M. Hinton and L. E. Mortenson, “Identification of Molybdoproteins in Clostridium pasteurianum,” Journal of Bacteriology, Vol. 162, No. 2, 1985, pp. 477-484.

[20]   A. W. Schüttelkopf, J. A. Harrison, D. H. Boxer and W. N. Hunter, “Passive Acquisition of Ligand by the MopII Molbindin from Clostridium pasteurianum: Structures of Apo and Oxyanion-Bound Forms,” Journal of Biological Chemistry, Vol. 277, No. 17, 2002, pp. 15013-15020.

[21]   U. G. Wagner, E. Stupperich and C. Kratky, “Structure of the Molybdate/Tungstate Binding Protein Mop from Sporomusa ovata,” Structure, Vol. 8, No. 11, 2000, pp. 1127-1136.

[22]   A. K. Duhme, W. Meyer-Klaucke, D. J. White, L. Delarbre, L. A. Mitchenall and R. N. Pau, “Extended X-Ray Absorption Fine Structure Studies on Periplasmic and Intracellular Molybdenum-Binding Proteins,” Journal of Biological and Inorganic Chemistry, Vol. 4, No. 5, 1999, 588-592.

[23]   J. B. Glass, F. L. Wolfe-Simon, J. J. Elser and A. D. Anbar, “Molybdenum-Nitrogen Co-Limitation in Freshwater and Coastal Heterocystous Cyanobacteria,” Limnology and Oceanography, Vol. 55, No. 2, 2010, pp. 667-676.

[24]   A. L. Zerkle, C. H. House, R. P. Cox and D. E. Canfield, “Metal Limitation of Cyanobacterial N2 Fixation and Implications for the Precambrian Nitrogen Cycle,” Geobiology, Vol. 4, 2006, pp. 285-297.

[25]   T. Thiel, “Characterization of Genes for an Alternative Nitrogenase in the Cyanobacterium Anabaena variabilis,” Journal of Bacteriology, Vol. 175, No. 19, 1993, pp. 6276-6286.

[26]   T. Thiel, B. Pratte and M. Zahalak, “Transport of Molybdate in the Cyanobacterium Anabaena variabilis ATCC 29413,” Archives of Microbiology, Vol. 179, No. 1, 2002, pp. 50-56.

[27]   M. Zahalak, B. Pratte, K. J. Werth and T. Thiel, “Molybdate Transport and Its Effect on Nitrogen Utilization in the Cyanobacterium Anabaena variabilis ATCC 29413,” Molecular Microbiology, Vol. 51, No. 2, 2004, pp. 539-549.

[28]   A. L. Zerkle, K. Scheiderich, J. A. Maresca, L. J. Liermann and S. L. Brantley, “Molybdenum Isotope Fractionation by Cyanobacterial Assimilation during Nitrate Utilization and N2 Fixation,” Geobiology, Vol. 9, No. 1, 2011, pp. 94-106.

[29]   S. M. Hinton and L. E. Mortenson, “Regulation and Order of Involvement of Molybdoproteins during Synthesis of Molybdoenzymes in Clostridium pasteurianum,” Journal of Bacteriology, Vol. 162, No. 2, 1985, pp. 485-493.

[30]   K. Makdessi, K. Fritsche, A. Pich and J. R. Andreesen, “Identification and Characterization of the Cytoplasmic Tungstate/Molybdate-Binding Protein (Mop) from Eubacterium acidaminophilum,” Archives of Microbiology, Vol. 181, No. 1, 2004, pp. 45-51.

[31]   J. Wiethaus, A. Wirsing, F. Narberhaus and B. Masepohl, “Overlapping and Specialized Functions of the Molybdenum-Dependent Regulators MopA and MopB in Rhodobacter capsulatus?” Journal of Bacteriology, Vol. 188, No. 24, 2006, pp. 8441-8451.

[32]   L. M. Rubio and P. W. Ludden, “Biosynthesis of the Iron-Molybdenum Cofactor of Nitrogenase,” Annual Reviews in Microbiology, Vol. 62, No. 1, 2008, pp. 93-111.

[33]   J. A. Hernandez, L. Curatti, C. P. Aznar, Z. Perova, R. D. Britt and L. M. Rubio, “Metal Trafficking for Nitrogen Fixation: nifQ Donates Molybdenum to NifEN/NifH for the Biosynthesis of the Nitrogenase FeMo-Cofactor,” Proceedings of the National Academy of Sciences, Vol. 105, No. 33, 2008, pp. 11679-11684.

[34]   J. Imperial, R. A. Ugalde, V. K. Shah and W. J. Brill, “Role of the nifQ Gene Product in the Incorporation of Molybdenum into Nitrogenase in Klebsiella pneumoniae,” Journal of Bacteriology, Vol. 158, No. 1,1984, pp. 187-194.

[35]   H. Bohme, “Regulation of Nitrogen Fixation in Hetero-cyst-Forming Cyanobacteria,” Trends in Plant Science, Vol. 3, No. 9, 1998, pp. 346-351.