Details

Autor(en) / Beteiligte

• Wu, Jun
• Chen, Ruohong
• Zhang, Caihui
• Li, Kangbai
• Xu, Weiying
• Wang, Lijuan
• Chen, Qingmei
• Mu, Peiqiang
• Jiang, Jun
• Wen, Jikai
• Deng, Yiqun

Titel

Bioactivation and Regioselectivity of Pig Cytochrome P450 3A29 towards Aflatoxin B1

Ist Teil von

• Toxins, 2016-09, Vol.8 (9), p.267

Ort / Verlag

MDPI

Erscheinungsjahr

2016

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Due to unavoidable contaminations in feedstuff, pigs are easily exposed to aflatoxin B 1 (AFB 1 ) and suffer from poisoning, thus the poisoned products potentially affect human health. Heretofore, the metabolic process of AFB 1 in pigs remains to be clarified, especially the principal cytochrome P450 oxidases responsible for its activation. In this study, we cloned CYP3A29 from pig liver and expressed it in Escherichia coli , and its activity has been confirmed with the typical P450 CO-reduced spectral characteristic and nifedipine-oxidizing activity. The reconstituted membrane incubation proved that the recombinant CYP3A29 was able to oxidize AFB 1 to form AFB 1 -exo-8,9-epoxide in vitro. The structural basis for the regioselective epoxidation of AFB 1 by CYP3A29 was further addressed. The T309A mutation significantly decreased the production of AFBO, whereas F304A exhibited an enhanced activation towards AFB 1 . In agreement with the mutagenesis study, the molecular docking simulation suggested that Thr309 played a significant role in stabilization of AFB 1 binding in the active center through a hydrogen bond. In addition, the bulk phenyl group of Phe304 potentially imposed steric hindrance on the binding of AFB 1 . Our study demonstrates the bioactivation of pig CYP3A29 towards AFB 1 in vitro, and provides the insight for understanding regioselectivity of CYP3A29 to AFB 1 .