title: Pa0148 from Pseudomonas aeruginosa catalyzes the deamination of adenine.
abstract: 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 10(5) M(-1) s(-1). 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 (β/α)(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.
authors.affiliation: Department of Chemistry, P.O. Box 30012, Texas A&M University , College Station, Texas 77843-3012, United States.
authors.forename: Alissa M
authors.initials: AM
authors.lastname: Goble
authors.forename: Zhening
authors.initials: Z
authors.lastname: Zhang
authors.forename: J Michael
authors.initials: JM
authors.lastname: Sauder
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Burley
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Swaminathan
authors.forename: Frank M
authors.initials: FM
authors.lastname: Raushel
mesh_terms: D000243:Adenosine Deaminase / Q000737:chemistry* / Q000378:metabolism; D000581:Amidohydrolases / Q000737:chemistry / Q000378:metabolism; D001173:Arthrobacter / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D003641:Deamination; D008024:Ligands; D017433:Protein Structure, Secondary; D011550:Pseudomonas aeruginosa / Q000201:enzymology*; D040681:Structural Homology, Protein; D013329:Structure-Activity Relationship; D013379:Substrate Specificity; D015032:Zinc / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; D000581:Amidohydrolases; D000243:Adenosine Deaminase; D015032:Zinc