Characterization of representative enzymes from a sulfate reducing bacterium implicated in the corrosion of steel,
Pereira, A. S., Franco R., Feio M. J., Pinto C., Lampreia J., Reis M. A., Calvete J., Moura I., Beech I., Lino A. R., and Moura J. J. G.
, Biochemical And Biophysical Research Communications, Volume {221}, Number {2}, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495, p.{414-421}, (1996)
AbstractThis communication reports the isolation, purification and characterization of key enzymes involved in dissimilatory sulfate reduction of a sulfate reducing bacterium classified as Desulfovibrio desulfuricans subspecies desulfuricans New Jersey (NCIMB 8313) (Ddd NJ). The chosen strain, originally recovered from a corroding cast iron heat exchanger, was grown in large scale batch cultures. Physico-chemical and spectroscopic studies of the purified enzymes were carried out. These analyses revealed a high degree of similarity between proteins isolated from the DddNJ strain and the homologous proteins obtained from Desulfomicrobium baculatus Norway 4. In view of the results obtained, taxonomic reclassification of Desulfovibrio desulfuricans subspecies desulfuricans New Jersey (NCIMB 8313) into Desulfomicrobium baculatus (New Jersey) is proposed. (C) 1996 Academic Press, Inc.
Cloning of a novel Mo-Cu containing protein from Desulfovibrio.gigas,
Di Rocco, G., Pereira A. S., Bursakov S. A., Gavel O. Y., Rusnak F., Lampreia J., Moura J. J. G., and Moura I.
, Journal Of Inorganic Biochemistry, Aug, Volume {86}, Number {1}, 655 AVENUE OF THE AMERICAS, NEW YORK, NY 10010 USA, p.{202}, (2001)
Abstractn/a
Conformations generated during turnover of the Azotobacter vinelandii nitrogenase MoFe protein and their relationship to physiological function,
Fisher, Karl, Lowe David J., Tavares Pedro, Pereira Alice S., Huynh Boi Hanh, Edmondson Dale, and Newton William E.
, Journal Of Inorganic Biochemistry, Nov, Volume {101}, Number {11-12}, p.{1649-1656}, (2007)
AbstractVarious S = 3/2 EPR signals elicited from wild-type and variant Azotobacter vinelandii nitrogenase MoFe proteins appear to reflect different conformations assumed by the FeMo-cofactor with different protonation states. To determine whether these presumed changes in protonation and conformation reflect catalytic capacity, the responses (particularly to changes in electron flux) of the alpha H195Q, alpha H195N, and alpha Q191 K variant MoFe proteins (where His at position 195 in the alpha subunit is replaced by Gln/Asn or Gln at position alpha-191 by Lys), which have strikingly different substrate-reduction properties, were studied by stopped-flow or rapid-freeze techniques. Rapid-freeze EPR at low electron flux (at 3-fold molar excess of wild-type Fe protein) elicited two transient FeMo-cofactor-based EPR signals within 1 s of initiating turnover under N-2 with the alpha H195Q and alpha H195N variants, but not with the alpha Q191K variant. No EPR signals attributable to P cluster oxidation were observed for any of the variants under these conditions. Furthermore, during turnover at low electron flux with the wild-type, alpha H195Q or alpha H195N MoFe protein, the longer-time 430-nm absorbance increase, which likely reflects P cluster oxidation, was also not observed (by stopped-flow spectrophotometry); it did, however, occur for all three MoFe proteins under higher electron flux. No 430-nm absorbance increase occurred with the alpha Q191K variant, not even at higher electron flux. This putative lack of involvement of the P cluster in electron transfer at low electron flux was confirmed by rapid-freeze Fe-57 Mossbauer spectroscopy, which clearly showed FeMo-factor reduction without P cluster oxidation. Because the wild-type, alpha H195Q and alpha H195N MoFe proteins can bind N-2, but alpha Q195K cannot, these results suggest that P cluster oxidation occurs only under high electron flux as required for N-2 reduction. (C) 2007 Elsevier Inc. All rights reserved.