ATP sulfurylase from the hyperthermophilic chemolithotroph Aquifex aeolicus

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• 作者：Hanna ; Eissa ; MacRae ; Ian J. ; Medina ; Daniel C. ; Fisher ; Andrew J. ; Segel ; Irwin H.
• 关键词：ATP sulfurylase ; from Aquifex aeolicus ; Adenylylsulfate (APS) kinase ; from Aquifex aeolicus ; hyperthermophile ; ATP sulfurylase from ; Chemolithotroph ; ATP sulfurylase ; and APS kinase in ; Sulfurylase ; from a hyperthermophilic bacterium ; Chemolithotroph ; sul
• 刊名：Archives of Biochemistry and Biophysics
• 出版年：2002
• 期刊代码：116_00039861
• 类别：ch
• 出版时间：October 15, 2002
• 卷：406
• 期：2
• 页码：275-288
• 文件大小：470 K

摘要

ATP sulfurylase from the hyperthermophilic chemolithotroph Aquifex aeolicus is a bacterial ortholog of the enzyme from filamentous fungi. (The subunit contains an adenosine 5^′-phosphosulfate (APS) kinase-like, C-terminal domain.) The enzyme is highly heat stable with a half-life >1h at 90°C. Steady-state kinetics are consistent with a random A–B, ordered P–Q mechanism where A=MgATP, B=SO₄²⁻, P=PP_i, and Q=APS. The kinetic constants suggest that the enzyme is optimized to act in the direction of ATP+sulfate formation. Chlorate is competitive with sulfate and with APS. In sulfur chemolithotrophs, ATP sulfurylase provides an efficient route for recycling PP_i produced by biosynthetic reactions. However, the protein possesses low APS kinase activity. Consequently, it may also function to produce PAPS for sulfate ester formation or sulfate assimilation when hydrogen serves as the energy source and a reduced inorganic sulfur source is unavailable.