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Charbonneau AA, Reicks EJ, Cambria JF, Inman J, Danley D, Shockley EA, Davion R, Salgado I, Norton EG, Corbett LJ, Hanacek LE, Jensen JG, Kibodeaux MA, Kirkpatrick TK, Rausch KM, Roth SR, West B, Wilson KE, Lawrence CM, Cloninger MJ. CUREs for high-level Galectin-3 expression. Protein Expr Purif 2024; 221:106516. [PMID: 38801985 DOI: 10.1016/j.pep.2024.106516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 05/21/2024] [Accepted: 05/25/2024] [Indexed: 05/29/2024]
Abstract
Galectins are a large and diverse protein family defined by the presence of a carbohydrate recognition domain (CRD) that binds β-galactosides. They play important roles in early development, tissue regeneration, immune homeostasis, pathogen recognition, and cancer. In many cases, studies that examine galectin biology and the effect of manipulating galectins are aided by, or require the ability to express and purify, specific members of the galectin family. In many cases, E. coli is employed as a heterologous expression system, and galectin expression is induced with isopropyl β-galactoside (IPTG). Here, we show that galectin-3 recognizes IPTG with micromolar affinity and that as IPTG induces expression, newly synthesized galectin can bind and sequester cytosolic IPTG, potentially repressing further expression. To circumvent this putative inhibitory feedback loop, we utilized an autoinduction protocol that lacks IPTG, leading to significantly increased yields of galectin-3. Much of this work was done within the context of a course-based undergraduate research experience, indicating the ease and reproducibility of the resulting expression and purification protocols.
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Affiliation(s)
| | - Elizabeth J Reicks
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - John F Cambria
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Jacob Inman
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Daria Danley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Emmie A Shockley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Ravenor Davion
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Isabella Salgado
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Erienne G Norton
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Lucy J Corbett
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Lucy E Hanacek
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Jordan G Jensen
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Marguerite A Kibodeaux
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Tess K Kirkpatrick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Keilen M Rausch
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Samantha R Roth
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Bernadette West
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Kenai E Wilson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - C Martin Lawrence
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA
| | - Mary J Cloninger
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, 59717, USA.
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Characterization of Galectin Fusion Proteins with Glycoprotein Affinity Columns and Binding Assays. Molecules 2023; 28:molecules28031054. [PMID: 36770718 PMCID: PMC9919667 DOI: 10.3390/molecules28031054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/11/2023] [Accepted: 01/15/2023] [Indexed: 01/21/2023] Open
Abstract
Galectins are β-galactosyl-binding proteins that fulfill essential physiological functions. In the biotechnological field, galectins are versatile tools, such as in the development of biomaterial coatings or the early-stage diagnosis of cancer diseases. Recently, we introduced galectin-1 (Gal-1) and galectin-3 (Gal-3) as fusion proteins of a His6-tag, a SNAP-tag, and a fluorescent protein. We characterized their binding in ELISA-type assays and their application in cell-surface binding. In the present study, we have constructed further fusion proteins of galectins with fluorescent protein color code. The fusion proteins of Gal-1, Gal-3, and Gal-8 were purified by affinity chromatography. For this, we have prepared glycoprotein affinity resins based on asialofetuin (ASF) and fetuin and combined this in a two-step purification with Immobilized Metal Affinity chromatography (IMAC) to get pure and active galectins. Purified galectin fractions were analyzed by size-exclusion chromatography. The binding characteristics to ASF of solely His6-tagged galectins and galectin fusion proteins were compared. As an example, we demonstrate a 1.6-3-fold increase in binding efficiency for HSYGal-3 (His6-SNAP-yellow fluorescent protein-Gal-3) compared to the HGal-3 (His6-Gal-3). Our results reveal an apparent higher binding efficiency for galectin SNAP-tag fusion proteins compared to His6-tagged galectins, which are independent of the purification mode. This is also demonstrated by the binding of galectin fusion proteins to extracellular glycoconjugates laminin, fibronectin, and collagen IV. Our results indicate the probable involvement of the SNAP-tag in apparently higher binding signals, which we discuss in this study.
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