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Irshad B, Lu C, Nederstigt AE, Hu P, Xue L, Lin-Cereghino J, Franz AH, Harrison JS, Lin-Cereghino GP. The effect of the bgs13 mutation on the structure of the reporter protein beta-lactoglobulin: Influence on folding and aggregation in Pichia pastoris. Protein Expr Purif 2023; 212:106355. [PMID: 37598731 PMCID: PMC10528908 DOI: 10.1016/j.pep.2023.106355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 08/22/2023]
Abstract
Pichia pastoris, a methylotrophic yeast used for recombinant protein expression, has the capability of performing many eukaryotic post-translational modifications, growing to high cell densities, and producing proteins in a cost-effective manner. However, P. pastoris's secretion properties are not always efficient, and its secretory pathway mechanisms have not been thoroughly elucidated. A previously identified mutant strain, bgs13, was found to efficiently secrete most recombinant proteins tested, raising the possibility that this bgs13 mutant is a universal super secreter. In this study, we used a reporter protein, β-lactoglobulin (b-LG), to perform structural analysis of the protein secreted from wild type and mutant bgs13 strains to investigate the secretory mechanism. Primary, secondary, and tertiary structures of b-LG were examined using Edman sequencing, circular dichroism, tryptophan fluorescence, and temperature induced aggregation analysis. Our results demonstrate that the bgs13 produced more b-LG than the wt strain and that this protein was functionally folded similar to the wt. Surprisingly, we also found that the bgs13 b-LG was more resistant to aggregation, providing another example of the superior qualities of this strain for enhanced secreted protein production.
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Affiliation(s)
- Bushra Irshad
- Department of Biological Sciences, University of the Pacific, Stockton, CA, 95211, USA
| | - Cai Lu
- Department of Chemistry, University of the Pacific, Stockton, CA, 95211, USA
| | - Anneroos E Nederstigt
- Biomolecular Mass Spectrometry and Proteomics, Utrecht University, Utrecht, the Netherlands
| | - Priscilla Hu
- Department of Biological Sciences, University of the Pacific, Stockton, CA, 95211, USA
| | - Liang Xue
- Department of Chemistry, University of the Pacific, Stockton, CA, 95211, USA
| | - Joan Lin-Cereghino
- Department of Biological Sciences, University of the Pacific, Stockton, CA, 95211, USA
| | - Andreas H Franz
- Department of Chemistry, University of the Pacific, Stockton, CA, 95211, USA
| | - Joseph S Harrison
- Department of Chemistry, University of the Pacific, Stockton, CA, 95211, USA.
| | - Geoff P Lin-Cereghino
- Department of Biological Sciences, University of the Pacific, Stockton, CA, 95211, USA.
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West JD. Experimental Approaches for Investigating Disulfide-Based Redox Relays in Cells. Chem Res Toxicol 2022; 35:1676-1689. [PMID: 35771680 DOI: 10.1021/acs.chemrestox.2c00123] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Reversible oxidation of cysteine residues within proteins occurs naturally during normal cellular homeostasis and can increase during oxidative stress. Cysteine oxidation often leads to the formation of disulfide bonds, which can impact protein folding, stability, and function. Work in both prokaryotic and eukaryotic models over the past five decades has revealed several multiprotein systems that use thiol-dependent oxidoreductases to mediate disulfide bond reduction, formation, and/or rearrangement. Here, I provide an overview of how these systems operate to carry out disulfide exchange reactions in different cellular compartments, with a focus on their roles in maintaining redox homeostasis, transducing redox signals, and facilitating protein folding. Additionally, I review thiol-independent and thiol-dependent approaches for interrogating what proteins partner together in such disulfide-based redox relays. While the thiol-independent approaches rely either on predictive measures or standard procedures for monitoring protein-protein interactions, the thiol-dependent approaches include direct disulfide trapping methods as well as thiol-dependent chemical cross-linking. These strategies may prove useful in the systematic characterization of known and newly discovered disulfide relay mechanisms and redox switches involved in oxidant defense, protein folding, and cell signaling.
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Affiliation(s)
- James D West
- Biochemistry & Molecular Biology Program, Departments of Biology and Chemistry, The College of Wooster, Wooster, Ohio 44691, United States
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