The cytochrome ba3 oxygen reductase from Thermus thermophilus uses a single input channel for proton delivery to the active site and for proton pumping.

ABSTRACT: The heme-copper oxygen reductases are redox-driven proton pumps that generate a proton motive force in both prokaryotes and mitochondria. These enzymes have been divided into 3 evolutionarily related groups: the A-, B- and C-families. Most experimental work on proton-pumping mechanisms has been performed with members of the A-family. These enzymes require 2 proton input pathways (D- and K-channels) to transfer protons used for oxygen reduction chemistry and for proton pumping, with the D-channel transporting all pumped protons. In this work we use site-directed mutagenesis to demonstrate that the ba(3) oxygen reductase from Thermus thermophilus, a representative of the B-family, does not contain a D-channel. Rather, it utilizes only 1 proton input channel, analogous to that of the A-family

SUBMITTER: Chang HY 

PROVIDER: S-EPMC2752507 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature