Dong, Z.; Yang, S.; Zhang, K.; Tang, C.; Kan, Y.; Yao, L. Biochemical Characterization of a Novel Alkaline-Tolerant Xaa-Pro Dipeptidase from Aspergillus phoenicis. Fermentation2023, 9, 978.
Dong, Z.; Yang, S.; Zhang, K.; Tang, C.; Kan, Y.; Yao, L. Biochemical Characterization of a Novel Alkaline-Tolerant Xaa-Pro Dipeptidase from Aspergillus phoenicis. Fermentation 2023, 9, 978.
Dong, Z.; Yang, S.; Zhang, K.; Tang, C.; Kan, Y.; Yao, L. Biochemical Characterization of a Novel Alkaline-Tolerant Xaa-Pro Dipeptidase from Aspergillus phoenicis. Fermentation2023, 9, 978.
Dong, Z.; Yang, S.; Zhang, K.; Tang, C.; Kan, Y.; Yao, L. Biochemical Characterization of a Novel Alkaline-Tolerant Xaa-Pro Dipeptidase from Aspergillus phoenicis. Fermentation 2023, 9, 978.
Abstract
Xaa-Pro dipeptidase (XPD, EC 3.4.13.9; also known as prolidase) catalyzes the hydrolysis of iminopeptide bond in the trans Xaa-Pro dipeptides (Xaa represents any amino acid except proline), which makes it find wide applications in food, medical and environmental protection fields. In the present study, a novel Xaa-Pro dipeptidase from Aspergillus phoenicis ATCC 14332 (ApXPD) was molecularly and biochemically characterized. Reclassification based on phylogenetic analysis and version 12.5 MEROPS database showed that this enzyme was the only fungal XPD in the unassigned subfamily which shared the highest sequence similarity with Xanthomonas campestris prolidase but not with that from the more related fungal species A. niudulans. As compared with other prolidases, ApXPD also contained an N-terminal tail (residues 81-89) and an additional region (PAPARLREKL), and used a different arginine residue for dipeptide selectivity. After heterologous expression and partial purification, recombinant ApXPD was highly active and stable over the alkaline range from 8.5 to 10.0, with a maximum activity at pH 9.0 and more than 80% activity retained after 1-h incubation at pHs of 8.5-10.0 (55oC). It also had an apparent optimum temperature of 55oC and remained stable at 20-30oC. Moreover, this enzyme was a cobalt dependent prolidase that only cleaved dipeptides Lys-Pro, Gly-Pro and Ala-Pro rather than other dipeptides, tripeptides and tetrapeptides. All these distinct features make A. phoenicis ATCC 14332 XPD unique among currently known prolidases, thus defining a novel Xaa-Pro dipeptidase subfamily.
Biology and Life Sciences, Biology and Biotechnology
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