Pa0148 from Pseudomonas aeruginosa Catalyzes the Deamination of Adenine

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• 作者：Alissa M. Goble ; Zhening Zhang ; J. Michael Sauder ; Stephen K. Burley ; Subramanyam Swaminathan ; Frank M. Raushel
• 刊名：Biochemistry
• 出版年：2011
• 出版时间：August 2, 2011
• 年：2011
• 卷：50
• 期：30
• 页码：6589-6597
• 全文大小：1093K
• 年卷期：v.50,no.30(August 2, 2011)
• ISSN：1520-4995

文摘

Four proteins from NCBI cog1816, previously annotated as adenosine deaminases, have been subjected to structural and functional characterization. Pa0148 (Pseudomonas aeruginosa PAO1), AAur1117 (Arthrobacter aurescens TC1), Sgx9403e, and Sgx9403g have been purified and their substrate profiles determined. Adenosine is not a substrate for any of these enzymes. All of these proteins will deaminate adenine to produce hypoxanthine with k_cat/K_m values that exceed 10⁵ M^鈥? s^鈥?. These enzymes will also accept 6-chloropurine, 6-methoxypurine, N-6-methyladenine, and 2,6-diaminopurine as alternate substrates. X-ray structures of Pa0148 and AAur1117 have been determined and reveal nearly identical distorted (尾/伪)₈ barrels with a single zinc ion that is characteristic of members of the amidohydrolase superfamily. Structures of Pa0148 with adenine, 6-chloropurine, and hypoxanthine were also determined, thereby permitting identification of the residues responsible for coordinating the substrate and product.