Pohorelic Brant K J, Voordouw Johanna K, Lojou Elisabeth, Dolla Alain, Harder Jens, Voordouw Gerrit
Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada.
J Bacteriol. 2002 Feb;184(3):679-86. doi: 10.1128/JB.184.3.679-686.2002.
The physiological properties of a hyd mutant of Desulfovibrio vulgaris Hildenborough, lacking periplasmic Fe-only hydrogenase, have been compared with those of the wild-type strain. Fe-only hydrogenase is the main hydrogenase of D. vulgaris Hildenborough, which also has periplasmic NiFe- and NiFeSe-hydrogenases. The hyd mutant grew less well than the wild-type strain in media with sulfate as the electron acceptor and H(2) as the sole electron donor, especially at a high sulfate concentration. Although the hyd mutation had little effect on growth with lactate as the electron donor for sulfate reduction when H(2) was also present, growth in lactate- and sulfate-containing media lacking H(2) was less efficient. The hyd mutant produced, transiently, significant amounts of H(2) under these conditions, which were eventually all used for sulfate reduction. The results do not confirm the essential role proposed elsewhere for Fe-only hydrogenase as a hydrogen-producing enzyme in lactate metabolism (W. A. M. van den Berg, W. M. A. M. van Dongen, and C. Veeger, J. Bacteriol. 173:3688-3694, 1991). This role is more likely played by a membrane-bound, cytoplasmic Ech-hydrogenase homolog, which is indicated by the D. vulgaris genome sequence. The physiological role of periplasmic Fe-only hydrogenase is hydrogen uptake, both when hydrogen is and when lactate is the electron donor for sulfate reduction.
对缺乏周质仅含Fe氢化酶的希登伯勒脱硫弧菌hyd突变体的生理特性与野生型菌株进行了比较。仅含Fe氢化酶是希登伯勒脱硫弧菌的主要氢化酶，该菌还具有周质NiFe-和NiFeSe-氢化酶。在以硫酸盐作为电子受体、H₂作为唯一电子供体的培养基中，hyd突变体的生长不如野生型菌株，尤其是在高硫酸盐浓度下。尽管当也存在H₂时，hyd突变对以乳酸作为硫酸盐还原电子供体的生长影响不大，但在缺乏H₂的含乳酸和硫酸盐的培养基中生长效率较低。在这些条件下，hyd突变体短暂产生大量H₂，最终这些H₂都用于硫酸盐还原。结果并不支持其他地方提出的仅含Fe氢化酶在乳酸代谢中作为产氢酶的关键作用（W. A. M. van den Berg、W. M. A. M. van Dongen和C. Veeger，《细菌学杂志》173:3688 - 3694，1991）。希登伯勒脱硫弧菌基因组序列表明，这个作用更可能由膜结合的胞质Ech-氢化酶同源物发挥。周质仅含Fe氢化酶的生理作用是氢摄取，无论是在氢作为还是乳酸作为硫酸盐还原电子供体时。
