Development of Therapeutic Chimeric Uricase by Exon Replacement/Restoration and Site-Directed Mutagenesis
AbstractThe activity of urate oxidase was lost during hominoid evolution, resulting in high susceptibility to hyperuricemia and gout in humans. In order to develop a more “human-like” uricase for therapeutic use, exon replacement/restoration and site-directed mutagenesis were performed to obtain porcine–human uricase with higher homology to deduced human uricase (dHU) and increased uricolytic activity. In an exon replacement study, substitution of exon 6 in wild porcine uricase (wPU) gene with corresponding exon in dhu totally abolished its activity. Substitutions of exon 5, 3, and 1–2 led to 85%, 60%, and 45% loss of activity, respectively. However, replacement of exon 4 and 7–8 did not significantly change the enzyme activity. When exon 5, 6, and 3 in dhu were replaced by their counterparts in wpu, the resulting chimera H1-2P3H4P5-6H7-8 was active, but only about 28% of wPU. Multiple sequence alignment and homology modeling predicted that mutations of E24D and E83G in H1-2P3H4P5-6H7-8 were favorable for further increase of its activity. After site-directed mutagenesis, H1-2P3H4P5-6H7-8 (E24D & E83G) with increased homology (91.45%) with dHU and higher activity and catalytic efficiency than the FDA-approved porcine–baboon chimera (PBC) was obtained. It showed optimum activity at pH 8.5 and 35 °C and was stable in a pH range of 6.5–11.0 and temperature range of 20–40 °C. View Full-Text
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Xie, G.; Yang, W.; Chen, J.; Li, M.; Jiang, N.; Zhao, B.; Chen, S.; Wang, M.; Chen, J. Development of Therapeutic Chimeric Uricase by Exon Replacement/Restoration and Site-Directed Mutagenesis. Int. J. Mol. Sci. 2016, 17, 764.
Xie G, Yang W, Chen J, Li M, Jiang N, Zhao B, Chen S, Wang M, Chen J. Development of Therapeutic Chimeric Uricase by Exon Replacement/Restoration and Site-Directed Mutagenesis. International Journal of Molecular Sciences. 2016; 17(5):764.Chicago/Turabian Style
Xie, Guangrong; Yang, Weizhen; Chen, Jing; Li, Miaomiao; Jiang, Nan; Zhao, Baixue; Chen, Si; Wang, Min; Chen, Jianhua. 2016. "Development of Therapeutic Chimeric Uricase by Exon Replacement/Restoration and Site-Directed Mutagenesis." Int. J. Mol. Sci. 17, no. 5: 764.
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