Cdr1p highlights the role of the non-hydrolytic ATP-binding site in driving drug translocation in asymmetric ABC pumps

Publication date: Available online 14 November 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Atanu Banerjee, Alexis Moreno, Mohammad Firoz Khan, Remya Nair, Suman Sharma, Sobhan Sen, Alok Kumar Mondal, Jorgaq Pata, Cédric Orelle, Pierre Falson, Rajendra PrasadAbstractATP-binding cassette (ABC) transporters couple ATP binding and hydrolysis to the translocation of allocrites across membranes. Two shared nucleotide-binding sites (NBS) participate in this cycle. In asymmetric ABC pumps, only one of them hydrolyzes ATP, and the functional role of the other remains unclear. Using a drug-based selection strategy on the transport-deficient mutant L529A in the transmembrane domain of the Candida albicans pump Cdr1p; we identified a spontaneous secondary mutation restoring drug-translocation. The compensatory mutation Q1005H was mapped 60 Å away, precisely in the ABC signature sequence of the non-hydrolytic NBS. The same was observed in the homolog Cdr2p. Both the mutant and suppressor proteins remained ATPase active, but remarkably, the single Q1005H mutant displayed a two-fold reduced ATPase activity and a two-fold increased drug-resistance as compared to the wild-type protein, pointing at a direct control of the non-hydrolytic NBS in substrate-translocation through ATP binding in asymmetric ABC pumps.Graphical abstract
Source: Biochimica et Biophysica Acta (BBA) Biomembranes - Category: Biochemistry Source Type: research