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Cell free protein synthesis versus yeast expression - A comparison using insulin as a model protein. Protein Expr Purif 2021; 186:105910. [PMID: 34089870 DOI: 10.1016/j.pep.2021.105910] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 11/20/2022]
Abstract
Expression of recombinant proteins traditionally require a cellular system to transcribe and translate foreign DNA to a desired protein. The process requires special knowledge of the specific cellular metabolism in use and is often time consuming and labour intensive. A cell free expression system provides an opportunity to express recombinant proteins without consideration of the living cell. Instead, a cell free system relies on either a cellular lysate or recombinant proteins to carry out protein synthesis, increasing overall production speed and ease of handling. The one-pot cell free setup is commonly known as an in vitro transcription/translation reaction (IVTT). Here we focused on a PURE (Protein synthesis Using Recombinant Elements) IVTT system based on recombinant proteins from Escherichia coli. We evaluated the cell free system's ability to express functional insulin analogues compared to Saccharomyces cerevisiae, a well-established system for large scale production of recombinant human insulin and insulin analogues. Significantly, it was found that correct insulin expression and folding was governed by the inherent properties of the primary amino acids sequence of insulin, whereas the eukaryotic features of the expression system apparently play a minor role. The IVTT system successfully produced insulin analogues identical in structure and with similar insulin receptor affinity to those produced by yeast. In conclusion we demonstrate that the PURE IVTT system is highly suited for expressing soluble molecules with higher order features and multiple disulphide bridges.
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Kjeldsen T, Hogendorf WFJ, Tornøe CW, Anderson J, Hubalek F, Stidsen CE, Sorensen JL, Hoeg-Jensen T. Dually Reactive Long Recombinant Linkers for Bioconjugations as an Alternative to PEG. ACS OMEGA 2020; 5:19827-19833. [PMID: 32803078 PMCID: PMC7424725 DOI: 10.1021/acsomega.0c02712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023]
Abstract
Covalent cross-linking of biomolecules can be useful in pursuit of tissue targeting or dual targeting of two receptors on cell surfaces for avidity effects. Long linkers (>10 kDa) can be advantageous for such purposes, and poly(ethylene glycol) (PEG) linkers are most commonly used due to the high aqueous solubility of PEG and its relative inertness toward biological targets. However, PEG is non-biodegradable, and available PEG linkers longer than 5 kDa are heterogeneous (polydisperse), which means that conjugates based on such materials will be mixtures. We describe here recombinant linkers of distinct lengths, which can be expressed in yeast, which are polar, and which carry orthogonal reactivity at each end of the linker, thus allowing chemoselective cross-linking of proteins. A conjugate between insulin and either of the two trypsin inhibitor peptides/proteins exemplifies the technology, using a GQAP-based linker of molecular weight of 17 848, having one amine at the N-terminal, and one Cys, at the C-terminal. Notably, yeast-based expression systems typically give products with mixed disulfides when expressing proteins that are equipped with one unpaired Cys, namely, mixed disulfides with glutathione, free Cys amino acid, and/or a protein homodimer. To obtain a homogeneous linker, we worked out conditions for transforming the linker with mixed disulfides into a linker with a homogeneous disulfide, using excess 4-mercaptophenylacetic acid. Subsequently, the N-terminal amine of the linker was transformed into an azide, and the C-terminal Cys disulfide was reduced to a free thiol and reacted with halo-acetyl insulin. The N-terminal azide was finally conjugated to either of the two types of alkyne-containing trypsin inhibitor peptides/proteins. This reaction sequence allowed the cross-linked proteins to carry internal disulfides, as no reduction step was needed after protein conjugations. The insulin-trypsin inhibitor conjugates were shown to be stabilized toward enzymatic digestions and to have partially retained binding to the insulin receptor.
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Østergaard M, Mishra NK, Jensen KJ. The ABC of Insulin: The Organic Chemistry of a Small Protein. Chemistry 2020; 26:8341-8357. [DOI: 10.1002/chem.202000337] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/15/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Mads Østergaard
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Narendra Kumar Mishra
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
| | - Knud J. Jensen
- Department of ChemistryUniversity of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg C Denmark
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Vinther TN, Kjeldsen TB, Jensen KJ, Hubálek F. The road to the first, fully active and more stable human insulin variant with an additional disulfide bond. J Pept Sci 2015; 21:797-806. [DOI: 10.1002/psc.2822] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 08/14/2015] [Accepted: 08/19/2015] [Indexed: 12/21/2022]
Affiliation(s)
| | | | - Knud J. Jensen
- Faculty of Science, Department of Chemistry; University of Copenhagen; DK-1871 Frederiksberg Denmark
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Vinther TN, Pettersson I, Huus K, Schlein M, Steensgaard DB, Sørensen A, Jensen KJ, Kjeldsen T, Hubalek F. Additional disulfide bonds in insulin: Prediction, recombinant expression, receptor binding affinity, and stability. Protein Sci 2015; 24:779-88. [PMID: 25627966 PMCID: PMC4420526 DOI: 10.1002/pro.2649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/26/2015] [Indexed: 11/07/2022]
Abstract
The structure of insulin, a glucose homeostasis-controlling hormone, is highly conserved in all vertebrates and stabilized by three disulfide bonds. Recently, we designed a novel insulin analogue containing a fourth disulfide bond located between positions A10-B4. The N-terminus of insulin's B-chain is flexible and can adapt multiple conformations. We examined how well disulfide bond predictions algorithms could identify disulfide bonds in this region of insulin. In order to identify stable insulin analogues with additional disulfide bonds, which could be expressed, the Cβ cut-off distance had to be increased in many instances and single X-ray structures as well as structures from MD simulations had to be used. The analogues that were identified by the algorithm without extensive adjustments of the prediction parameters were more thermally stable as assessed by DSC and CD and expressed in higher yields in comparison to analogues with additional disulfide bonds that were more difficult to predict. In contrast, addition of the fourth disulfide bond rendered all analogues resistant to fibrillation under stress conditions and all stable analogues bound to the insulin receptor with picomolar affinities. Thus activity and fibrillation propensity did not correlate with the results from the prediction algorithm. Statement: A fourth disulfide bond has recently been introduced into insulin, a small two-chain protein containing three native disulfide bonds. Here we show that a prediction algorithm predicts four additional four disulfide insulin analogues which could be expressed. Although the location of the additional disulfide bonds is only slightly shifted, this shift impacts both stability and activity of the resulting insulin analogues.
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Affiliation(s)
- Tine N Vinther
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | | | - Kasper Huus
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | - Morten Schlein
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | | | - Anders Sørensen
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
| | - Knud J Jensen
- Department of Chemistry, Faculty of Science, University of CopenhagenDK-1871, Frederiksberg, Denmark
| | - Thomas Kjeldsen
- Diabetes Research UnitNovo Nordisk A/S, DK-2760, Måløv, Denmark
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Vinther TN, Norrman M, Ribel U, Huus K, Schlein M, Steensgaard DB, Pedersen TÅ, Pettersson I, Ludvigsen S, Kjeldsen T, Jensen KJ, Hubálek F. Insulin analog with additional disulfide bond has increased stability and preserved activity. Protein Sci 2013; 22:296-305. [PMID: 23281053 DOI: 10.1002/pro.2211] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 12/04/2012] [Accepted: 12/07/2012] [Indexed: 11/10/2022]
Abstract
Insulin is a key hormone controlling glucose homeostasis. All known vertebrate insulin analogs have a classical structure with three 100% conserved disulfide bonds that are essential for structural stability and thus the function of insulin. It might be hypothesized that an additional disulfide bond may enhance insulin structural stability which would be highly desirable in a pharmaceutical use. To address this hypothesis, we designed insulin with an additional interchain disulfide bond in positions A10/B4 based on Cα-Cα distances, solvent exposure, and side-chain orientation in human insulin (HI) structure. This insulin analog had increased affinity for the insulin receptor and apparently augmented glucodynamic potency in a normal rat model compared with HI. Addition of the disulfide bond also resulted in a 34.6°C increase in melting temperature and prevented insulin fibril formation under high physical stress even though the C-terminus of the B-chain thought to be directly involved in fibril formation was not modified. Importantly, this analog was capable of forming hexamer upon Zn addition as typical for wild-type insulin and its crystal structure showed only minor deviations from the classical insulin structure. Furthermore, the additional disulfide bond prevented this insulin analog from adopting the R-state conformation and thus showing that the R-state conformation is not a prerequisite for binding to insulin receptor as previously suggested. In summary, this is the first example of an insulin analog featuring a fourth disulfide bond with increased structural stability and retained function.
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Affiliation(s)
- Tine N Vinther
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv DK-2760, Denmark
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Vinther TN, Norrman M, Strauss HM, Huus K, Schlein M, Pedersen TÅ, Kjeldsen T, Jensen KJ, Hubálek F. Novel covalently linked insulin dimer engineered to investigate the function of insulin dimerization. PLoS One 2012; 7:e30882. [PMID: 22363506 PMCID: PMC3281904 DOI: 10.1371/journal.pone.0030882] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 12/23/2011] [Indexed: 11/18/2022] Open
Abstract
An ingenious system evolved to facilitate insulin binding to the insulin receptor as a monomer and at the same time ensure sufficient stability of insulin during storage. Insulin dimer is the cornerstone of this system. Insulin dimer is relatively weak, which ensures dissociation into monomers in the circulation, and it is stabilized by hexamer formation in the presence of zinc ions during storage in the pancreatic β-cell. Due to the transient nature of insulin dimer, direct investigation of this important form is inherently difficult. To address the relationship between insulin oligomerization and insulin stability and function, we engineered a covalently linked insulin dimer in which two monomers were linked by a disulfide bond. The structure of this covalent dimer was identical to the self-association dimer of human insulin. Importantly, this covalent dimer was capable of further oligomerization to form the structural equivalent of the classical hexamer. The covalently linked dimer neither bound to the insulin receptor, nor induced a metabolic response in vitro. However, it was extremely thermodynamically stable and did not form amyloid fibrils when subjected to mechanical stress, underlining the importance of oligomerization for insulin stability.
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Affiliation(s)
- Tine N. Vinther
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
- Faculty of Life Sciences, IGM, University of Copenhagen, Frederiksberg, Denmark
| | - Mathias Norrman
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Holger M. Strauss
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Kasper Huus
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Morten Schlein
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Thomas Å. Pedersen
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Thomas Kjeldsen
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
| | - Knud J. Jensen
- Faculty of Life Sciences, IGM, University of Copenhagen, Frederiksberg, Denmark
| | - František Hubálek
- Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv, Denmark
- * E-mail:
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