AAA-ATPase proteins are ubiquitously present in all kingdoms of life to participate in diverse cellular processes, such as DNA replication, membrane fusion, and protein homeostasis. Canonical AAA proteins share a highly conserved ATP-binding domain, usually forming hexameric rings with a central pore that engages with substrates. Through sequential ATP-hydrolysis powered conformational change around the ring, the AAA subunits arrange in a spiral staircase fashion along the peptide/DNA string to grab and pull individual residues/nucleotide bases, resulting in stepwise substrate translocation. Bcs1 is a mitochondrial membrane bound AAA-ATPase that facilitates the assembly of the respiratory Complex III, by translocating the fully assembled iron-sulfur protein subunit (ISP) across the mitochondrial inner membrane. Recent structures of mouse and yeast Bcs1 determined in different nucleotide states revealed that, unlike typical AAA proteins, Bcs1 forms a homo-heptameric ring and its subunits lack the conserved substrate-contact pore loops. The Apo/ADP bound Bcs1 ring displayed a central cavity opening towards the mitochondrial matrix, which is sufficiently large to accommodate the fully folded ISP. Upon ATPγS binding, this cavity collapsed to one-third the size and could no longer accommodate folded ISP, which presumably represents a post-substrate translocation state. Although the ISP translocation cycle can be speculated from the available Bcs1 conformations, mechanistic details regarding how Bcs1 couples ATP hydrolysis with substrate transport remain elusive. To investigate this, we captured Bcs1 conformations during its active translocation cycle by incubating Bcs1 with ATP in the absence or presence of substrate for a given time before freezing the sample and analyzing using cryo-EM. Our results show that, unlike canonical AAA proteins, heptameric Bcs1 transits uniformly between ATP and ADP conformations with no co-existing nucleotide states, which strongly suggest that Bcs1 acts in a concerted mechanism.