bioRxiv preprint doi: https://doi.org/10.1101/528265; this version posted January 23, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 1 RESEARCH ARTICLE 2 3 A novel thermostable aspartic protease from Talaromyces leycettanus and its specific 4 autocatalytic activation through an intermediate transition state 5 6 Yujie Guo1, Tao Tu1, Yaxin Ren1, Yaru Wang1, Yingguo Bai1, Xiaoyun Su1, Yuan 7 Wang1, Bin Yao1, Huoqing Huang1*, Huiying Luo1* 8 9 1Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research 10 Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China 11 Running title: Insights into a specific auto-activation of proTlAPA1 12 * Corresponding authors. 13 E-mail addresses:
[email protected] (H. Luo),
[email protected] (H. Huang). 2 bioRxiv preprint doi: https://doi.org/10.1101/528265; this version posted January 23, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 14 ABSTRACT 15 Aspartic proteases exhibit optimum enzyme activity under acidic condition and 16 have been extensively used in food, fermentation and leather industries. In this study, 17 a novel aspartic protease precursor (proTlAPA1) from Talaromyces leycettanus was 18 identified and successfully expressed in Pichia pastoris. Subsequently, the 19 auto-activation processing of the zymogen proTlAPA1 was studied by SDS-PAGE 20 and N-terminal sequencing, under different processing conditions. TlAPA1 shared the 21 highest identity of 70.3 % with the aspartic endopeptidase from Byssochlamys 22 spectabilis (GAD91729) and was classified into a new subgroup of the aspartic 23 protease A1 family, based on evolutionary analysis.