Design and recombinant expression of insulin-like peptide 5 precursors and the preparation of mature human INSL5 |
| |
Authors: | Xiao Luo Ross A. D. Bathgate Wei-Jie Zhang Ya-Li Liu Xiao-Xia Shao John D. Wade Zhan-Yun Guo |
| |
Affiliation: | (1) Institute of Protein Research, Tongji University, 1239 Siping Road, Shanghai, 200092, China;(2) Florey Neuroscience Institutes, Howard Florey Institute, The University of Melbourne, Melbourne, VIC, 3010, Australia;(3) Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, 3010, Australia;(4) Central Laboratory, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, 200120, China;(5) School of Chemistry, The University of Melbourne, Melbourne, VIC, 3010, Australia; |
| |
Abstract: | Insulin-like peptide 5 (INSL5) is a recently identified insulin superfamily member. Although it binds to and activates the G-protein coupled receptor, RXFP4, its precise biological function remains unknown. To help determine its function, significant quantities of INSL5 are required. In the present work, three single-chain INSL5 precursors were designed, two of which were successfully expressed in E. coli cells. The expressed precursors were solubilized from inclusion bodies, purified almost to homogeneity by immobilized metal-ion affinity chromatography, and then refolded in vitro. One precursor could be converted to two-chain human INSL5 bearing an extended N-terminus of the A-chain (designated long-INSL5) by sequential Lys-C endoproteinase and carboxypeptidase B treatment. The 6 residue A-chain N-terminal extension of long-INSL5 was subsequently removed by Aeromonas aminopeptidase to yield native INSL5 that was designated short-INSL5. Circular dichroism spectroscopic analysis and peptide mapping showed that the recombinant INSL5s adopted an insulin-like conformation and possessed the expected characteristic insulin-like disulfide linkages. Activity assay showed that both long- and short-INSL5 had full RXFP4 receptor activity compared with chemically synthesized human INSL5. This suggested that extension of the N-terminus of the A-chain of long-INSL5 did not adversely impact upon the binding to or activation of the RXFP4 receptor. However, the single-chain INSL5 precursor was inactive which indicated that a free C-terminus of the B-chain is critical for the activity of INSL5. Our present work thus provides an efficient approach for preparation of INSL5 and its analogs through recombinant expression in E. coli cells. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|