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Németh BZ, Nagy ZA, Kiss B, Gellén G, Schlosser G, Demcsák A, Geisz A, Hegyi E, Sahin-Tóth M, Pál G. Substrate specificity of human chymotrypsin-like protease (CTRL) characterized by phage display-selected small-protein inhibitors. Pancreatology 2023; 23:742-749. [PMID: 37604733 PMCID: PMC10528761 DOI: 10.1016/j.pan.2023.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 08/15/2023] [Indexed: 08/23/2023]
Abstract
Chymotrypsin-like protease (CTRL) is one of the four chymotrypsin isoforms expressed in the human exocrine pancreas. Human genetic and experimental evidence indicate that chymotrypsins B1, B2, and C (CTRB1, CTRB2 and CTRC) are important not only for protein digestion but also for protecting the pancreas against pancreatitis by degrading potentially harmful trypsinogen. CTRL has not been reported to play a similar role, possibly due to its low abundance and/or different substrate specificity. To address this problem, we investigated the specificity of the substrate-binding groove of CTRL by evolving the substrate-like canonical loop of the Schistocerca gregaria proteinase inhibitor 2 (SGPI-2), a small-protein reversible chymotrypsin inhibitor to bind CTRL. We found that phage-associated SGPI-2 variants with strong affinity to CTRL were similar to those evolved previously against CTRB1, CTRB2 or bovine chymotrypsin A (bCTRA), indicating comparable substrate specificity. When tested as recombinant proteins, SGPI-2 variants inhibited CTRL with similar or slightly weaker affinity than bCTRA, confirming that CTRL is a typical chymotrypsin. Interestingly, an SGPI-2 variant selected with a Thr29His mutation in its reactive loop was found to inhibit CTRL strongly, but it was digested rapidly by bCTRA. Finally, CTRL was shown to degrade human anionic trypsinogen, however, at a much slower rate than CTRB2, suggesting that CTRL may not have a significant role in the pancreatic defense mechanisms against inappropriate trypsinogen activation and pancreatitis.
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Affiliation(s)
- Bálint Zoltán Németh
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117, Budapest, Hungary
| | - Zoltán Attila Nagy
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117, Budapest, Hungary
| | - Bence Kiss
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117, Budapest, Hungary
| | - Gabriella Gellén
- Department of Analytical Chemistry, MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/A, Budapest, H-1117, Budapest, Hungary
| | - Gitta Schlosser
- Department of Analytical Chemistry, MTA-ELTE Lendület Ion Mobility Mass Spectrometry Research Group, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/A, Budapest, H-1117, Budapest, Hungary
| | - Alexandra Demcsák
- Department of Surgery, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Andrea Geisz
- Department of Surgery, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Eszter Hegyi
- Institute for Translational Medicine, University of Pécs, Medical School, H-7624, Pécs, Hungary
| | - Miklós Sahin-Tóth
- Department of Surgery, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Gábor Pál
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117, Budapest, Hungary.
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