The periplasmic linker protein component of an organic solvent and antibiotic efflux pump; confers resistance to toluene, hexane, p-xylene, ampicillin, penicillin G, erythromycin, novobiocin and tetracycline. Belongs to the membrane fusion protein (MFP) (TC 8.A.1) family. There are 4 nearly identical operons in various strains of P.putida. This one and the ttgABC operon of strain DOT-T1E function in solvent and antibiotic efflux; however in strain S12 the arpABC operon functions only in antibiotic efflux. This may be due to different protein expression levels. In strain KT2440 the equivalent operon does not seem to function in toluene efflux.