Expression and purification of E. coli BirA biotin ligase for in vitro biotinylation

Protein Production Core Facility, Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA.
Protein Expression and Purification (Impact Factor: 1.7). 03/2012; 82(1):162-7. DOI: 10.1016/j.pep.2011.12.008
Source: PubMed


The extremely tight binding between biotin and avidin or streptavidin makes labeling proteins with biotin a useful tool for many applications. BirA is the Escherichia coli biotin ligase that site-specifically biotinylates a lysine side chain within a 15-amino acid acceptor peptide (also known as Avi-tag). As a complementary approach to in vivo biotinylation of Avi-tag-bearing proteins, we developed a protocol for producing recombinant BirA ligase for in vitro biotinylation. The target protein was expressed as both thioredoxin and MBP fusions, and was released from the corresponding fusion by TEV protease. The liberated ligase was separated from its carrier using HisTrap HP column. We obtained 24.7 and 27.6 mg BirA ligase per liter of culture from thioredoxin and MBP fusion constructs, respectively. The recombinant enzyme was shown to be highly active in catalyzing in vitro biotinylation. The described protocol provides an effective means for making BirA ligase that can be used for biotinylation of different Avi-tag-bearing substrates.

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Available from: Rui Sousa, Jun 12, 2015
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    • "Without biotin, we observe significant precipitation during purification with concomitant loss of mSA. The potential role of biotin as a molecular chaperone was demonstrated in the context of yeast display, in which addition of biotin to the growth medium was shown to help improve display efficiency of unstable mSA on the yeast surface (Lim et al. 2012). The importance of including biotin can be understood based on the structure of the binding pocket, which includes a structurally and functionally important disulfide bond (Demonte et al. 2013; Lim et al. 2013). "
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    ABSTRACT: We recently reported the engineering of monomeric streptavidin (mSA) for use in monomeric detection of biotinylated ligands. Although mSA can be expressed functionally on the surface of mammalian cells and yeast, the molecule does not fold correctly when expressed in Escherichia coli. Refolding from inclusion bodies is cumbersome and yields a limited amount of purified protein. Improving the final yield should facilitate its use in biotechnology. We tested the expression and purification of mSA fused to GST, MBP, thioredoxin, and sumo tags to simplify its purification and improve the yield. The fusion proteins can be expressed solubly in E. coli and increase the yield by more than 20-fold. Unmodified mSA can be obtained by proteolytically removing the fusion tag. Purified mSA can be immobilized on a solid matrix to purify biotinylated ligands. Together, expressing mSA as a fusion with a solubilization tag vastly simplifies its preparation and increases its usability in biotechnology.
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    ABSTRACT: BirA is a biotin ligase from Escherichia coli that specifically biotinylates a lysine side-chain within a 15-amino acid acceptor peptide (also known as Avi-tag). We developed a protocol for producing recombinant BirA ligase in E. coli for in vitro biotinylation (Li and Sousa, Prot Expr Purif, 82:162-167, 2012) in which the target protein was expressed as both thioredoxin and MBP fusions, and was released by TEV protease-mediated cleavage. The liberated ligase and the fusion proteins were enzymatically active. Based on that observation, we have now developed a novel system for in vivo biotinylation by co-expressing the Avi-tagged target protein with the MBP-BirA fusion. The effectiveness of this system was demonstrated by the successful in vivo labeling of antimicrobial protein, scygonadin. This new system shows improved efficiency compared with pre-existing one and this is likely attributed to the high expression level and solubility of the co-expressed MBP-BirA.
    No preview · Article · May 2012 · Biotechnology Letters
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    ABSTRACT: Scygonadin is an antimicrobial protein isolated from the mud crab, Scylla serrate. The mature protein comprises 102 amino acids and has a theoretical molecular weight of 11,272 Da. The protein's specific expression pattern strongly suggests that it plays a role in reproductive immunity. In this study, I developed a protocol for producing recombinant scygonadin in Escherichia coli. The target protein was expressed as both thioredoxin and SUMO fusions, and released by TEV and SUMO protease-mediated cleavages, respectively. In either case, the liberated scygonadin was separated from its carrier using a HisTrap HP column. From thioredoxin and SUMO fusion constructs, 32.7 and 29.2 mg target protein per liter of culture was obtained, respectively. The described protocol provides an effective means for producing scygonadin in relatively large quantities, which facilities its further characterization.
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