Lykkemark S, Mandrup OA, Friis NA, Kristensen P. Degradation of C-terminal tag sequences on domain antibodies purified from E. coli supernatant.
MAbs 2014;
6:1551-9. [PMID:
25426869 PMCID:
PMC4622476 DOI:
10.4161/mabs.36211]
[Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/18/2014] [Accepted: 08/23/2014] [Indexed: 11/19/2022] Open
Abstract
Expression of recombinant proteins often takes advantage of peptide tags expressed in fusion to allow easy detection and purification of the expressed proteins. However, as the fusion peptides most often are flexible appendages at the N- or C-terminal, proteolytic cleavage may result in removal of the tag sequence. Here, we evaluated the functionality and stability of 14 different combinations of commonly used tags for purification and detection of recombinant antibody fragments. The tag sequences were inserted in fusion with the c-terminal end of a domain antibody based on the HEL4 scaffold in a phagemid vector. This particular antibody fragment was able to refold on the membrane after blotting, allowing us to detect c-terminal tag breakdown by use of protein A in combination with detection of the tags in the specific constructs. The degradation of the c-terminal tags suggested specific sites to be particularly prone to proteolytic cleavage, leaving some of the tag combinations partially or completely degraded. This specific work illustrates the importance of tag design with regard to recombinant antibody expression in E. coli, but also aids the more general understanding of protein expression.
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