<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">CALDEIRA, J</style></author><author><style face="normal" font="default" size="100%">PALMA, PN</style></author><author><style face="normal" font="default" size="100%">REGALLA, M</style></author><author><style face="normal" font="default" size="100%">Lampreia, J</style></author><author><style face="normal" font="default" size="100%">Calvete, J</style></author><author><style face="normal" font="default" size="100%">SCHAFER, W</style></author><author><style face="normal" font="default" size="100%">LeGall, J</style></author><author><style face="normal" font="default" size="100%">Moura, I</style></author><author><style face="normal" font="default" size="100%">Moura, JJG</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">PRIMARY SEQUENCE, OXIDATION-REDUCTION POTENTIALS AND TERTIARY-STRUCTURE PREDICTION OF DESULFOVIBRIO-DESULFURICANS ATCC-27774 FLAVODOXIN</style></title><secondary-title><style face="normal" font="default" size="100%">EUROPEAN JOURNAL OF BIOCHEMISTRY</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1994</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAR 15</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">3</style></number><volume><style face="normal" font="default" size="100%">220</style></volume><pages><style face="normal" font="default" size="100%">987-995</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Flavodoxin was isolated and purified from Desulfovibrio desulfuricans ATCC 27774, a sulfatereducing organism that can also utilize nitrate as an alternative electron acceptor. Mid-point oxidation-reduction potentials of this flavodoxin were determined by ultraviolet/visible and EPR methods coupled to potentiometric measurements and their pH dependence studied in detail. The redox potential E(2), for the couple oxidized/semiquinone forms at pH 6.7 and 25 degrees C is -40 mV, while the value for the semiquinone/hydroquinone forms (E(1)), at the same pH, -387 mV. E(2) varies linearly with pH, while E(1) is independent of pH at high values. However, at low pH (&lt;7.0), this value is less negative, compatible with a redox-linked protonation of the flavodoxin hydroquinone. A comparative study is presented for Desulfovibrio salexigens NCIB 8403 flavodoxin {[}Moura, I., Moura, J. J. G., Bruschi, M. and LeGall, J. (1980) Biochim. Biophys. Acta 591, 1-8]. The complete primary amino acid sequence was obtained by automated Edman degradation from peptides obtained by chemical and enzymic procedures. The amino acid sequence was confirmed by FAB/MS. Using the previously determined tridimensional structure of Desulfovibrio vulgaris flavodoxin as a model {[}similarity, 48,6%; Watenpaugh, K. D., Sieker, L. C., Jensen, L. H., LeGall, J. and Dubourdieu M. (1972) Proc. Natl Acad. Sci. USA 69, 3185-3188], the tridimensional structure of D. desulfuricans ATCC 27774 flavodoxin was predicted using AMBER force-field calculations.</style></abstract></record></records></xml>