Facile Synthesis and Characterization of a Novel Tamavidin‐Luciferase Reporter Fusion Protein for Universal Signaling Applications

Despite the avidin/biotin reaction being one of the most ubiquitous noncovalent immobilization and sensing strategies in scientific research, the ability to synthesize useful amounts of biotin‐binding fusion constructs is hampered by poor solubility in bacterial expression systems. As such, there are few reports of successful genetic reporter fusions incorporating a biotin‐binding partner. To address this, a sensitivity‐enhanced, synthetically facile reporter fusion is developed to merge the bioluminescence output of Gaussia luciferase (Gluc) with the recently characterized biotin‐binding ability of tamavidin 2 (TA2) for general and universal signaling applications in biological and analytical systems. This fusion construct enables direct bacterial expression of a reporter system incorporating two important functionalities in a 1:1 stoichiometric relationship that can provide detection of discrete events at low concentrations. Using a cold‐shock expression system, highly concentrated construct can be obtained from standard culture volumes while retaining essentially native protein activity. To demonstrate feasibility and provide an example application, this fusion construct is then included in a standard target‐bridged assay design for the sensitive detection of four miRNA targets.