|Michael J. Maroney
Professor of Chemistry, University of Massachusetts
Ph.D.: University of Washington
The focus of the research in my group is on the elucidation of the structure and function of transition metal ions in biological systems by use of a wide variety of biophysical measurements (principally spectroscopic techniques) and the synthetic model approach. From spectroscopic measurements such as x-ray absorption, electronic absorption, IR, Raman, epr, NMR and ENDOR, we can probe the structure of the metal center and the nature of the ligand environment. Synthetic models are used to interpret spectroscopic results.
A recent interest has involved the biological function of Ni, which is now associated with five enzymes: hydrogenase, carbon monoxide dehydrogenase, methyl coenzyme M reductase, superoxide dismutase and urease. In the first three of these enzymes, Ni has been postulated to be a redox center. We have probed the redox role of the Ni center in Thiocapsa roseopersicina hydrogenase using x-ray absorption spectroscopic measurements on redox poised samples. These measurements fail to provide any support for a redox role for nickel, but do indicate that the Ni site is bound to the protein by S-donor ligands, some of which must be cysteinate ligands. Model studies point to the possible importance of the S-donor ligands in the chemistry associated with the Ni site.
E. Eren, D. C. Kennedy, M. J. Maroney, J. M. Arguello, “A novel regulatory metal binding domain is present in the C-terminus of Arabidopsis Zn+2-ATPase HMA2,” J. Biol. Chem. 2006 in press,
Ju, T., Goldsmith, R. B., Chai, S. C., Maroney, M. J., Pochapsky, S. S., Pochapsky, T. C., “One protein, two enzymes revisited: A structural entropy switch interconverts the two structural isoforms of acireductone dioxygenase,” J. Mol. Biol., 2006, 393, 823-234
S. C. Chai, J. R. Bruyere and M. J. Maroney, “Probes of the catalytic site of cysteine dioxygenase,” J. Biol. Chem., 2006, 281, 15774-15779
P. A. Bryngelson and M. J. Maroney, “Nickel Superoxide Dismutase,” Metal Ions in Living Systems, Vol 46, “Nickel and its Surprising Impact in Nature” Sigel, A., Sigel H., and Sigel R. K. O., eds., John Wiley and Sons, Ltd., Chichester, UK
B. S. Chohan and M. J. Maroney, Selective oxidations of a dithiolate complex produce a mixed sulfonate/thiolate complex, Inorg. Chem. 2006, 46, 1906 - 1908
T. E. Elgren, O. A. Zadvorny, E. Brecht, T. Douglas, N. A. Zorin, M. J. Maroney, and J. W. Peters, “Immobilization of Active Hydrogenases by Encapsulation in Polymeric Porous Gels,” Nano Letters 2005, 5, 2085-2087
P. A. Bryngelson, S.E. Arobo, J.L. Pinkham, D.E.Cabelli, and M.J. Maroney, “Expression, Reconstitution and Mutation of Recombinant Streptomyces coelicolor NiSOD,” J. Am. Chem. Soc. 2004 , 126, 460–461.
R.K. Szilagyi, P.A. Bryngelson, M. J. Maroney, B. Hedman, K.O. Hodgson, and E. I. Solomon, “S K-edge C-ray Absorption Spectroscopic Investigation of the Ni-containing Superoxide Dismutase Active Site,” J. Am. Chem. Soc. 2004 , 126, 3018 – 3019.
B. S. Chohan,S. C. Shoner,J. A. Kovacs,and M. J. Maroney, “Ligand Oxidations in High-Spin Nickel Thiolate Complexes and Zinc Analogues,” Inorg. Chem. 2004 , 43, 7726-7734.
S. C. Chai, A. A. Jerkins, J. J. Banik, I. Shalev, J. L. Pinkham, P. C. Uden and M. J. Maroney, “Heterologous Expression, Purification and Characterization of Recombinant Rat Cysteine Dioxygenase,” J. Biol. Chem. 2005, 280, 9865 – 9869.
Fiedler, A. T., Bryngelson, P. A., Maroney, M. J., Brunold, T. C., “Spectroscopic and Computational Studies of Ni Superoxide Dismutase: Electronic Structure Contributions to Enzymatic Function,” J. Am. Chem. Soc. 2005 , 127 , 5449 – 5462.
O. A. Kharenko, D. C. Kennedy, B. Demeler, M. J. Maroney, and M. Y. Ogawa, “Cu(I) Luminescence from the Tetranuclear Cu4S4 Cofactor of a Synthetic 4-Helix Bundle,” J. Am. Chem. Soc. 2005 , 127, 7678 - 7679.
T. E. Elgren, O. A. Zadvorny, E. Brecht, T. Douglas, N. A. Zorin, M. J. Maroney, and J. W. Peters, “Immobilization of Active Hydrogenases by Encapsulation in Polymeric Porous Gels,” Nano Letters 2005 , in press (available on ASAP).
P. E. Carrington, P. T. Chivers, F. Al-Mjeni, R. T. Sauer and M. J. Maroney, Nickel coordination is regulated by the DNA-bound state of NikR,” Nature Struct. Biol. 2003 , 10, 126-130.
Al-Mjeni, F., T. Ju, T. C. Pochapsky and M. J. Maroney (2002). "XAS Investigation of the Structure and Function of Ni in Acireductone Dioxygenase." Biochemistry 41(21): 6761-9.
Davidson, G., S. L. Clugston, J. F. Honek and M. J. Maroney (2001). "An XAS
Maroney, M. J. and P. A. Bryngelson (2001). "Spectroscopic and model studies of the Ni-Fe hydrogenase reaction mechanism." J Biol Inorg Chem 6(4): 453-9.
Magnuson, T. S., N. Isoyama, A. L. Hodges-Myerson, G. Davidson, M. J. Maroney, G. G. Geesey and D. R. Lovley (2001). "Isolation, characterization and gene sequence analysis of a membrane-associated 89 kDa Fe(III) reducing cytochrome c from Geobacter sulfurreducens." Biochem J 359(Pt 1): 147-52.
Davidson, G., S. B. Choudhury, Z. Gu, K. Bose, W. Roseboom, S. P. Albracht and M. J. Maroney (2000). "Structural examination of the nickel site in chromatium vinosum hydrogenase: redox state oscillations and structural changes accompanying reductive activation and CO binding." Biochemistry 39(25): 7468-79.
Davidson, G., S. L. Clugston, J. F. Honek and M. J. Maroney (2000). "XAS investigation of the nickel active site structure in Escherichia coli glyoxalase I." Inorg Chem 39(14): 2962-3.
Maroney, M. J. (1999). "Structure/function relationships in nickel metallobiochemistry." Curr Opin Chem Biol 3(2): 188-99.
Choudhury, S. B., J. W. Lee, G. Davidson, Y. I. Yim, K. Bose, M. L. Sharma, S. O. Kang, D. E. Cabelli and M. J. Maroney (1999). "Examination of the nickel site structure and reaction mechanism in Streptomyces seoulensis superoxide dismutase." Biochemistry 38(12): 3744-52.
Huyett, J. E., S. B. Choudhury, D. M. Eichhorn, P. A. Bryngelson, M. J. Maroney and B. M. Hoffman (1998). "Pulsed ENDOR and ESEEM Study of [Bis(maleonitriledithiolato)nickel](-): An Investigation into the Ligand Electronic Structure." Inorg Chem 37(6): 1361-1367.
Allan, C. B., G. Davidson, S. B. Choudhury, Z. Gu, K. Bose, R. O. Day and M. J. Maroney (1998). "Protonation and Alkylation of a Dinuclear Nickel Thiolate Complex." Inorg Chem 37(17): 4166-4167.