Abstract
Deep-sea anoxic brine pools of the Red Sea are considered oneof the most remote and extreme environments on Earth whileremaining one of the least studied. High salt concentrations(4.3 M), elevated temperatures (up to 68 ̊C) and high metal con-tent make them promising sources for novel enzymes with struc-tures distinguished by evolutionary adaption. Reliable functionalannotation of genomic data is the key-step in the discovery ofnovel enzymes. Therefore we developed a Profile & PatternMatching algorithm to eliminate false positive annotations. Basedon scientific and industrial interest 13 genes were selected and arecurrently expressed in halophilic expression systems.One of the most interesting genes identified might open novelclass of Mn2+dependent alcohol dehydrogenases. The enzyme isextremely tolerant to different salt concentrations (ranging frommillimolar to saturation) and high solvent concentrations, showsa broad substrate spectra and is stable at both, high temperatures(up to 85°C) and basic pH. More interesting is the altered activ-ity by substitution with different metal ions, where in opposite toin silicopredictions Fe2+shows no effect on activity. The enzymeis slightly activated with Zn2+but shows an activation boostwith Mn2+. The activity profile at different temperatures, salt,pH, aggregation temperature, hydrodynamic radius and the sub-strate spectra changed significantly between Zn2+or Mn2+addi-tion, representing the natural environment at the brine pool oforigin. Currently ongoing crystal structure determinations willhelp identify the structural adaption and are likely to open newroutes for green catalysts.