Pereira, Inês CardosoSantos, André Fernando2017-04-192018-12-012015-12-172015-12http://hdl.handle.net/10362/20506Life on Earth is extremely diverse, as organisms had to adapt to a panoply of different environmental niches. There are several mechanisms by which organisms grow in the absence of oxygen, one of which is the dissimilatory reduction of sulfate to sulfide, performed by sulfate reducing prokaryotes (SRP). This is thought to be one of the most ancient biological metabolisms to have developed on earth. In SRP sulfate is first imported to the cytoplasm where it is activated by Sulfate adenylyl transferase to adenosine 5′-phosphosulfate (APS) in an ATP consuming process. After, the adenylyl-sulfate reductase is the enzyme responsible for the reduction of APS to sulfite.(...)engdoctoral thesis