A concerted ATPase cycle of the protein transporter AAA-ATPase Bcs1.

ABSTRACT: Bcs1, a homo-heptameric transmembrane AAA-ATPase, facilitates folded Rieske iron-sulfur protein translocation across the inner mitochondrial membrane. Structures in different nucleotide states (ATPγS, ADP, apo) provided conformational snapshots, but the kinetics and structural transitions of the ATPase cycle remain elusive. Here, using high-speed atomic force microscopy (HS-AFM) and line scanning (HS-AFM-LS), we characterized single-molecule Bcs1 ATPase cycling. While the ATP conformation had ~5600 ms lifetime, independent of the ATP-concentration, the ADP/apo conformation lifetime was ATP-concentration dependent and reached ~320 ms at saturating ATP-concentration, giving a maximum turnover rate of 0.17 s^-1. Importantly, Bcs1 ATPase cycle conformational changes occurred in conce

SUBMITTER: Pan Y 

PROVIDER: S-EPMC10567702 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature