Novel hydrogenases from deep-sea hydrothermal vents

该项目旨在从化学性质不同的深海热液喷口系统的宏基因组中鉴定和表征新的氢吸收酶（氢化酶）。由于深海热液喷口系统通常以氢浓度升高为特征，并且初级生物质生产依赖于化学能，这些环境为微生物氢氧化物提供了巨大的潜力。在我们之前的DFG项目中，我们建立了一个基于活性的筛选，使我们能够从宏基因组fosmid文库中识别重组氢摄取活性酶。我们已经发现了六个新的氢摄取活性宏基因组克隆。他们的宏基因组片段与公共数据库中的条目显示出很大程度上低（或没有）序列同源性。在本研究项目中，我们拟从富氢热液生境中构建两个新的宏基因组fosmid文库，筛选fosmid克隆的吸氢活性，测定各自的酶活性，并鉴定宏基因组片段上编码吸氢活性酶的基因。新的氢化酶及其附属基因的成功鉴定将扩大我们对氢化酶的多样性和生化特性以及参与氢化酶成熟和激活的基因和蛋白质的认识。

The project aims at identifying and characterizing novel hydrogen uptake enzymes (hydrogenases) from metagenomes of chemically distinct deep-sea hydrothermal vent systems. As deep-sea hydrothermal vent systems usually are characterized by elevated hydrogen concentrations and the primary biomass production depends on chemical energy, these environments provide a large potential for microbial hydrogen oxidizers. In the course of our previous DFG project we established an activity-based screen which enables us to identify recombinant hydrogen uptake active enzymes from metagenomic fosmid libraries. We already discovered six new hydrogen uptake active metagenomic clones. Their metagenomic fragments exhibited largely low (or no) sequence homologies to entries in the public databases. In the here described research project we propose to construct two new metagenomic fosmid libraries from hydrogen-rich hydrothermal habitats, screen the fosmid clones for hydrogen uptake activity, determine respective enzyme activity and identify the genes on the metagenomic fragments that encode enzymes responsible for the hydrogen uptake activity. The successful identification of novel hydrogenases and their accessory genes will expand our knowledge on the diversity and biochemical properties of hydrogenases and the genes and proteins involved in hydrogenase maturation and activation.