USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates St., Houston, TX 77030-2600, United States.
Microbiol Res. 2011 Oct 20;166(7):531-8. doi: 10.1016/j.micres.2010.11.002. Epub 2011 Jan 15.
Although it is known that oxalic acid provides a selective advantage to the secreting microbe our understanding of how this acid is biosynthesized remains incomplete. This study reports the identification, cloning, and partial characterization of the oxalic acid biosynthetic enzyme from the animal bacterial pathogen, Burkholderia mallei. The discovered gene was named oxalate biosynthetic component (obc)1. Complementation of Burkholderia oxalate defective (Bod)1, a Burkholderia glumae mutant that lacks expression of a functional oxalic acid biosynthetic operon, revealed that the obc1 was able to rescue the no oxalate mutant phenotype. This single gene rescue is in contrast to the situation found in B. glumae which required the expression of two genes, obcA and obcB, to achieve complementation. Enzyme assays showed that even though the two Burkholderia species differed in the number of genes required to encode a functional enzyme, both catalyzed the same acyl-CoA dependent biosynthetic reaction. In addition, mutagenesis studies suggested a similar domain structure of the assembled oxalate biosynthetic enzymes whether encoded by one or two genes.
尽管已知草酸为分泌微生物提供了选择性优势，但我们对这种酸如何生物合成的理解仍不完整。本研究报告了动物细菌病原体伯克霍尔德菌的草酸生物合成酶的鉴定、克隆和部分特性。发现的基因被命名为草酸生物合成成分（obc）1。伯克霍尔德菌草酸缺陷型（Bod）1的互补实验，这是一种伯克霍尔德菌 glumae 突变体，缺乏功能性草酸生物合成操纵子的表达，表明 obc1 能够挽救无草酸突变体的表型。这种单基因挽救与伯克霍尔德菌 glumae 的情况形成对比，后者需要表达两个基因 obcA 和 obcB 才能实现互补。酶活性测定表明，尽管两种伯克霍尔德菌在编码功能酶所需的基因数量上存在差异，但它们都催化相同的酰基辅酶 A 依赖性生物合成反应。此外，诱变研究表明，即使由一个或两个基因编码，组装的草酸生物合成酶也具有相似的结构域结构。
