Balcke Gerd Ulrich, Wegener Silke, Kiesel Bärbel, Benndorf Dirk, Schlömann Michael, Vogt Carsten
Department of Hydrogeology, UFZ, Helmholtz Centre for Environmental Research, Theodor-Lieser-Strasse 4, Halle/Saale, Germany.
Biodegradation. 2008 Jul;19(4):507-18. doi: 10.1007/s10532-007-9156-0. Epub 2007 Oct 13.
Focussing on the role of chlorocatechol 1,2-dioxygenase (CC12O), an oxygen-dependent key enzyme in the aerobic catabolism of chlorobenzene (CB), Pseudomonas veronii strain UFZ B549, Acidovorax facilis strain UFZ B530, and a community of indigenous groundwater bacteria were amended with CB degradation under either oxic or hypoxic conditions. All cultures readily degraded CB at high oxygen availability, but had differing abilities to completely degrade CB when exposed to oxygen limitation. For the three cultures very distinct oxygen half-saturation constants (0.3-11.7 muM) for the respective CC12Os were obtained and protein analysis showed that high affinity-type A. facilis and low affinity-type P. veronii express CC12Os, which belong to different structural clusters. From this a functional relation between CC12O type and the ability to cope with efficient ring fission under oxygen limitation is anticipated. Extremely high oxygen affinities for CC12Os support the assumption that truly oxic environments are not an essential requirement to degrade chloro(aromatic) compounds. Tiny quantities of oxygen permanently re-supplied will sufficiently maintain the growth of microaerophilic specialists with the ability to transform chloro(aromatics) via catechol intermediates.
聚焦于氯邻苯二酚1,2 -双加氧酶（CC12O）的作用，它是氯苯（CB）好氧分解代谢中的一种氧依赖性关键酶，在有氧或缺氧条件下，对维罗纳假单胞菌菌株UFZ B549、嗜酸栖热菌菌株UFZ B530以及一个原生地下水细菌群落进行了CB降解实验。在高氧条件下，所有培养物都能快速降解CB，但在氧气受限的情况下，它们完全降解CB的能力有所不同。对于这三种培养物，分别获得了各自CC12O非常不同的氧半饱和常数（0.3 - 11.7 μM），蛋白质分析表明，高亲和力型的嗜酸栖热菌和低亲和力型的维罗纳假单胞菌表达的CC12O属于不同的结构簇。由此预计CC12O类型与在氧气受限条件下有效进行环裂解的能力之间存在功能关系。CC12O具有极高的氧亲和力，这支持了这样一种假设，即真正的有氧环境并非降解氯（芳香）化合物的必要条件。持续重新供应微量氧气将足以维持具有通过邻苯二酚中间体转化氯（芳香族化合物）能力的微需氧专性菌的生长。
