ABC Transporter: Atm1 and the Transport of Heavy Metals

Abstract

ATP binding cassette (ABC) active transporters rely on the ability to bind and hydrolyze ATP with the purpose of exporting and importing molecules into and out of cells. In this study, we focus on Atm1, an ABC transporter originally discovered in yeast mitochondria. Atm1 plays a critical role in iron sulfur cluster synthesis, although the exact mechanism is not known. The protein utilized in this research is NaAtm1, from Novosphingobium aromaticivorans, which has been shown to confer heavy metal resistance when overexpressed in E. coli. The overall goal of this research is to confirm that the Atm1 that we are working with does indeed transport heavy metals, and to understand how Atm1 mediates this transport. Toward this end, four mutants of the Atm1 protein were created to dissect the mechanism of transport. The first mutant was made in the Walker B motif and is expected to be ATP hydrolysis deficient. This mutant was created by knocking out the catalysis ability of the protein by replacing a glutamate with a glutamine (E523Q). The second mutant, S526C, will be fluorescently tagged to observe changes in conformation when the protein is bound to nucleotides and/or substrate. The third mutant, K142Q, is designed to uncouple ATP hydrolysis and transport. The last mutant, K400A, is expected to eliminate the ability to bind ATP by changing a lysine to an alanine in the Walker A motif. This collection of mutations will allow us to begin our dissection of the NaAtm1 mechanism.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.