Structural highlights
FunctionPublication Abstract from PubMedThe alternation of substrate specificity expands the application range of enzymes in industrial, medical, and pharmaceutical fields. l-Glutamate oxidase (LGOX) from Streptomyces sp. X-119-6 catalyzes the oxidative deamination of l-glutamate to produce 2-ketoglutarate with ammonia and hydrogen peroxide. LGOX shows strict substrate specificity for l-glutamate. Previous studies on LGOX revealed that Arg305 in its active site recognizes the side chain of l-glutamate, and replacement of Arg305 by other amino acids drastically changes the substrate specificity of LGOX. Here we demonstrate that the R305E mutant variant of LGOX exhibits strict specificity for l-arginine. The oxidative deamination activity of LGOX to l-arginine is higher than that of l-arginine oxidase form from Pseudomonas sp. TPU 7192. X-ray crystal structure analysis revealed that the guanidino group of l-arginine is recognized not only by Glu305 but also Asp433, Trp564, and Glu617, which interact with Arg305 in wild-type LGOX. Multiple interactions by these residues provide strict specificity and high activity of LGOX R305E toward l-arginine. LGOX R305E is a thermostable and pH stable enzyme. The amount of hydrogen peroxide, which is a byproduct of oxidative deamination of l-arginine by LGOX R305E, is proportional to the concentration of l-arginine in a range from 0 to 100 muM. The linear relationship is maintained around 1 muM of l-arginine. Thus, LGOX R305E is suitable for the determination of l-arginine. A new l-arginine oxidase engineered from l-glutamate oxidase.,Yano Y, Matsuo S, Ito N, Tamura T, Kusakabe H, Inagaki K, Imada K Protein Sci. 2021 Mar 25. doi: 10.1002/pro.4070. PMID:33764624[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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