Rapp-Giles B J, Casalot L, English R S, Ringbauer J A, Dolla A, Wall J D
Biochemistry Department, University of Missouri-Columbia, Columbia, Missouri 65211, USA.
Appl Environ Microbiol. 2000 Feb;66(2):671-7. doi: 10.1128/AEM.66.2.671-677.2000.
To explore the physiological role of tetraheme cytochrome c(3) in the sulfate-reducing bacterium Desulfovibrio desulfuricans G20, the gene encoding the preapoprotein was cloned, sequenced, and mutated by plasmid insertion. The physical analysis of the DNA from the strain carrying the integrated plasmid showed that the insertion was successful. The growth rate of the mutant on lactate with sulfate was comparable to that of the wild type; however, mutant cultures did not achieve the same cell densities. Pyruvate, the oxidation product of lactate, served as a poor electron source for the mutant. Unexpectedly, the mutant was able to grow on hydrogen-sulfate medium. These data support a role for tetraheme cytochrome c(3) in the electron transport pathway from pyruvate to sulfate or sulfite in D. desulfuricans G20.
为探究四血红素细胞色素c(3)在硫酸盐还原菌脱硫脱硫弧菌G20中的生理作用，编码前体蛋白的基因被克隆、测序，并通过质粒插入进行突变。对携带整合质粒的菌株的DNA进行物理分析表明插入成功。突变体在乳酸盐与硫酸盐存在的情况下的生长速率与野生型相当；然而，突变体培养物未能达到相同的细胞密度。乳酸的氧化产物丙酮酸作为突变体的电子源效果不佳。出乎意料的是，突变体能够在氢气-硫酸盐培养基上生长。这些数据支持四血红素细胞色素c(3)在脱硫脱硫弧菌G20中从丙酮酸到硫酸盐或亚硫酸盐的电子传递途径中发挥作用。
