硫化氢是一种广泛分布的有毒气体，硫醌氧化还原酶（SQR）是微生物和动物代谢硫化氢的关键酶。本项目拟针对实验室分离的一株高效硫化物代谢化能自养菌- - 硫碱弧菌(Thialkalivibrio sp.)D301，开展SQR表达调控机制与进化的研究。利用生物信息学方法从硫碱弧菌基因组中寻找SQR基因序列，与蛋白质组学方法结合，确定硫碱弧菌SQR相关基因及其表达调控区域；利用兼并引物PCR、Tail-PCR、基因敲除/互补方法、报告基因融合表达、实时定量PCR、染色体步移、启动子缺失、定点突变等技术，研究不同条件下SQR基因转录和翻译情况，确定其调控序列、启动子序列、SQR酶编码区、信号肽、SQR在细胞中的定位等，并解析其酶学性质。通过项目的开展，将阐明硫碱弧菌SQR表达调控和进化机制，为自养和异养微生物及动物硫代谢研究提供借鉴，并将有助于天然气和沼气的生物脱硫过程强化。

Sulfide is a widely distributed poisonous gas. Sulfide:quinone oxidoreductase (SQR) is the key enzyme for the oxidation of sulfide to elemental sulfur in microorganisms and animals. In this research, the evolution and regulatory mechanism of the expression of SQR from Thialkalivibrio sp. D301, a novel haloalkaliphilic chemolithoautotrophic sulfide oxidizing bacteria separated from soda lakes in Inner Mongolia, will be studied. The promoter, functional gene and regulatory sequences for SQR will be identified via genome analysis and comparative proteomics. Biochemical and molecular biological methods, like degerate PCR, Tail-PCR, gene knockout/complementation method, fusion expression with reporter gene, real-time PCR, genome walking, promoter deletion, site-directed mutagenesis, will be adopted to explore the function of promoter, signal peptide and regulatory sequence. The transcriptional regulation mechanism of SQR will be investigated. Expression of SQR under different conditions will be analyzed. The enzymatic characteristics of SQR will be studied with purified SQR enzymes. Bioinformatics studies of SQR and regulatory sequence will be conducted to forecast the evolution of SQR in bacteria, archaea and animals (including human being). This research will be helpful to reveal the evolution and regulatory mechanism of the expression of SQR from Thialkalivibrio sp. D301. It will also provide technical support for the bioremediation of sulfide containing gases, like natural gas, biogas and landfill gas.