文献类型：期刊文献

英文题名：Exploring the Smallest Active Fragment of HsQSOX1b and Finding a Highly Efficient Oxidative Engine

作者：Zheng, Wenyun[1];Zhang, Wenyao[1];Hu, Wei[1];Zhang, Chao[1];Yang, Yi[1]

机构：[1]E China Univ Sci & Technol, Sch Pharm, State Key Lab Bioreactor Engn, Synthet Biol & Biotechnol Lab, Shanghai 200237, Peoples R China

年份：2012

卷号：7

期号：7

外文期刊名：PLOS ONE

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000306644600030)】；

基金：This work was supported by the 863 Program (Grant No. 2006AA02Z160), NSFC (National Nature Science Foundation of China) (Grant Nos. 90713026, 31071260 and 31170815), the Fok Ying Tung Education Foundation (Grant No. 111022), the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning, Dawn Program of Shanghai Education Commission (Grant No. 11SG31), the 111 Project (Grant No. B07023), and the Fundamental Research Funds for the Central Universities. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

语种：英文

摘要：Human quiescin-sulfhydryl oxidase 1 isoform b (HsQSOX1b) is a highly efficient, multiple-domain enzyme that directly inserts disulfide bonds into client protein. However, previous studies have focused mainly on the catalytic activity of the whole protein rather than its domain structure. In this research, we dissected the structure and function of HsQSOX1b and explored its mechanism as a highly efficient sulfhydryl oxidase by analyzing the truncated variants. The results showed that the first HsQSOX1b thioredoxin domain was essential for thiol oxidase activity. The smallest active fragment (SAQ) was identified to consist of a helix-rich region (HRR) and an essential for respiration and viability/augmenter of liver regeneration (ERV/ALR) domain, which remained highly active to oxidize an artificial non-thiol substrate but not small molecular and protein thiols. Our study clearly demonstrated that SAQ is a highly efficient oxidative engine, which shows high efficiency in the de novo disulfide formation and oxygen reduction and that this more efficient oxidative engine is necessary for the highly efficient catalysis of QSOXs compared to Erv1 and Erv2. This study will help address the roles of different HsQSOX1b domains in de novo disulfide formation and encourage the engineering of more efficient QSOX variants for the in vitro folding of disulfide-containing proteins.