1
|
Roy G, Reier J, Garcia A, Martin T, Rice M, Wang J, Prophet M, Christie R, Dall’Acqua W, Ahuja S, Bowen MA, Marelli M. Development of a high yielding expression platform for the introduction of non-natural amino acids in protein sequences. MAbs 2020; 12:1684749. [PMID: 31775561 PMCID: PMC6927762 DOI: 10.1080/19420862.2019.1684749] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 10/14/2019] [Accepted: 10/18/2019] [Indexed: 12/11/2022] Open
Abstract
The ability to genetically encode non-natural amino acids (nnAAs) into proteins offers an expanded tool set for protein engineering. nnAAs containing unique functional moieties have enabled the study of post-translational modifications, protein interactions, and protein folding. In addition, nnAAs have been developed that enable a variety of biorthogonal conjugation chemistries that allow precise and efficient protein conjugations. These are being studied to create the next generation of antibody-drug conjugates with improved efficacy, potency, and stability for the treatment of cancer. However, the efficiency of nnAA incorporation, and the productive yields of cell-based expression systems, have limited the utility and widespread use of this technology. We developed a process to isolate stable cell lines expressing a pyrrolysyl-tRNA synthetase/tRNApyl pair capable of efficient nnAA incorporation. Two different platform cell lines generated by these methods were used to produce IgG-expressing cell lines with normalized antibody titers of 3 g/L using continuous perfusion. We show that the antibodies produced by these platform cells contain the nnAA functionality that enables facile conjugations. Characterization of these highly active and robust platform hosts identified key parameters that affect nnAA incorporation efficiency. These highly efficient host platforms may help overcome the expression challenges that have impeded the developability of this technology for manufacturing proteins with nnAAs and represents an important step in expanding its utility.
Collapse
Affiliation(s)
- Gargi Roy
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Jason Reier
- Cell Culture and Fermentation Sciences, AstraZeneca, Gaithersburg, Maryland, USA
| | - Andrew Garcia
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Tom Martin
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Megan Rice
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Jihong Wang
- Analytical Sciences, AstraZeneca, Gaithersburg, Maryland, USA
| | - Meagan Prophet
- Analytical Sciences, AstraZeneca, Gaithersburg, Maryland, USA
| | - Ronald Christie
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - William Dall’Acqua
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Sanjeev Ahuja
- Cell Culture and Fermentation Sciences, AstraZeneca, Gaithersburg, Maryland, USA
| | - Michael A Bowen
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| | - Marcello Marelli
- Antibody Discovery and Protein Engineering, AstraZeneca, Gaithersburg, Maryland, USA
| |
Collapse
|
2
|
Stelter P, Hurt E. A pulse-chase epitope labeling to study cellular dynamics of newly synthesized proteins: a novel strategy to characterize NPC biogenesis and ribosome maturation/export. Methods Cell Biol 2014; 122:147-63. [PMID: 24857729 DOI: 10.1016/b978-0-12-417160-2.00007-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The vast number of cellular proteins performs their roles within macromolecular assemblies and functional cell networks. Hence, an understanding of how multiprotein complexes are formed and modified during biogenesis is a key problem in cell biology. Here, we describe a detailed protocol for a nonradioactive pulse-chase in vivo-labeling approach. The method is based on the incorporation of an unnatural amino acid (O-methyl-tyrosine) by the nonsense suppression of an amber stop codon that quickly fuses an affinity tag of choice to a protein of interest. This affinity tag could be used to directly isolate the newly synthesized proteins and hence allows for the characterization of early complex biogenesis intermediates. Combined with a tetracycline controllable riboswitch in the 5'-UTR of the respective mRNA, this approach became a versatile tool to study dynamic protein assembly within cellular networks (Stelter et al., 2012). In the context of this volume, this method notably provides a suitable approach to study NPC, ribosome and mRNP biogenesis, or nuclear protein translocation. This chapter includes detailed protocols to track newly synthesized, epitope pulsed-chased proteins by western blot, their assembly within complexes using immunoprecipitation, and their subcellular localization using indirect immunofluorescence or subcellular fractionation. While these protocols use budding yeast as model system, this method can be adapted to other model systems.
Collapse
Affiliation(s)
- Philipp Stelter
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld, Heidelberg, Germany
| | - Ed Hurt
- Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld, Heidelberg, Germany
| |
Collapse
|