DrkBiT is a membrane-impermeable peptide, a competitive peptide against HiBiT, that binds to LgBiT without recovering the Nluc activity reduced these background signals, and the signal to background ratio was dramatically improved. DrkBiT did not affect Fluc reporter signals.
Yamamoto M, Du Q, Song J, Wang H, Watanabe A, Tanaka Y, Kawaguchi Y, Inoue JI, Matsuda Z. Cell-cell and virus-cell fusion assay-based analyses of alanine insertion mutants in the distal α9 portion of the JRFL gp41 subunit from HIV-1. J Biol Chem. 2019 Apr 5;294(14):5677-5687. doi: 10.1074/jbc.RA118.004579. Epub 2019 Feb 8. PMID: 30737278; PMCID: PMC6462516.