Biochemistry and Molecular Genetics of Formate Utilization in Methanogenic Archaebacteria

在甲酸盐上生长所需的酶， 甲酸甲烷杆菌中的甲酸脱氢酶操纵子， 将被研究。 具体目标是确定 需要高效启动转录的高度 表达的甲酸脱氢酶操纵子使用体外无细胞 转录系统 预计结果将延长 目前对甲烷生成的看法超出了生物化学的理解， 揭示了古细菌基因表达的新规律。 长期目标是利用体内分子方法（即， 定点诱变），以研究（i） （ii）在古细菌中的转录，和（ii）生物化学 甲酸脱氢酶（和其他酶）的机制， 甲酸盐利用率这里提出的研究，连同工作， 正在开发一个转换系统，将奠定 这些长期目标的基础。 %%% 生物产甲烷的过程发生在各种不同的环境中。 厌氧栖息地，是一个重要组成部分，全球 碳循环 产甲烷生物是古细菌， 在遗传学上不同于真细菌和真核生物;因此， 对这些不寻常有机体的研究提供了第三个研究视角 基本的细胞过程 目前对 甲基化作用主要基于微生物和生物化学 问题研究 这项研究将结合分子遗传学和 生物化学方法来研究 甲酸盐依赖的CO2还原为甲烷。

The enzyme requirements for growth on formate, and expression of the formate dehydrogenase operon in Methanobacterium formicicum, will be studied. The specific aim is to identify the factors require for efficient initiation of transcription of the highly expressed formate dehydrogenase operon using an in vitro cell-free transcription system. The results are expected to extend the current view of methanogenesis beyond a biochemical understanding, and reveal new principles of gene expression in the archaebacteria. The long-term goal is to utilize in vivo molecular approaches (i.e. site-directed mutagenesis) to study (i) fundamental principles of transcription in the archaebacteria, and (ii) the biochemical mechanism of formate dehydrogenase (and other enzymes) required for formate utilization. The research proposed here, together with work in progress to develop a transformation system, will lay the foundation for these long-term goals. %%% The process of biological methanogenesis occurs in a variety of anaerobic habitats and is a significant component of the global carbon cycle. Methanogenic organisms are archaebacteria which are phylogenetically distinct from eubacteria and eukaryotes; thus, the study of these unusual organisms offer a third perspective to study fundamental cellular processes. The present understanding of methogenesis is largely based on microbiological and biochemical studies. This research will combines molecular genetic and biochemical approaches to investigate the pathway of formate-dependent CO2 reduction to methane.