title: A new sulfurtransferase from the hyperthermophilic bacterium Aquifex aeolicus. Being single is not so simple when temperature gets high.
abstract: Sulfur is a functionally important element of living matter. Rhodanese is involved in the enzymatic production of the sulfane sulfur which has been suggested as the biological relevant active sulfur species. Rhodanese domains are ubiquitous structural modules occurring in the three major evolutionary phyla. We characterized a new single-domain rhodanese with a thiosulfate : cyanide transferase activity, Aq-477. Aq-477 can also use tetrathionate and polysulfide. Thermoactivity and thermostability studies show that in solution Aquifex sulfurtranferase exists in equilibrium between monomers, dimers and tetramers, shifting to the tetrameric state in the presence of substrate. We show that oligomerization is important for thermostability and thermoactivity. This is the first characterization of a sulfurtransferase from a hyperthermophilic bacterium, which moreover presents a tetrameric organization. Oligomeric Aq-477 may have been selected in hyperthermophiles because subunit association provides extra stabilization.
authors: Laboratoire de Bioénergétique et Ingénierie des Protéines (BIP), IBSM-CNRS, Marseille, France.
authors: Marie-Cécile
authors: MC
authors: Giuliani
authors: Pascale
authors: P
authors: Tron
authors: Gisèle
authors: G
authors: Leroy
authors: Corinne
authors: C
authors: Aubert
authors: Patrick
authors: P
authors: Tauc
authors: Marie-Thérèse
authors: MT
authors: Giudici-Orticoni
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D001704:Biopolymers / Q000378:metabolism; D002384:Catalysis; D002850:Chromatography, Gel; D004795:Enzyme Stability; D007700:Kinetics; D013056:Spectrophotometry, Ultraviolet; D013466:Sulfurtransferases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D001704:Biopolymers; D013466:Sulfurtransferases