Focus protein: ATP synthase
Capturing energy for our cells
An enzyme is a protein that increases the rate of a reaction, often by at least a million times that of the uncatalysed reaction.
Calling adenosine triphosphate (ATP) synthase an enzyme hardly does it justice. True, it makes ATP, but the protein is an impressive nanoscale machine – a complex of proteins consisting of a transmembrane pump and two linked motors, which rotate.
Different forms of ATP synthase are found in bacteria and in the membranes of mitochondria and plant chloroplasts, but the enzyme’s general mechanism is conserved across organisms. As protons cross the membrane, down a concentration gradient, one motor turns, driving an axle that turns the other and producing ATP in the process. The axle driving the ATP-making enzyme rotates 150 times a second. The cleverest part is that these motors can be thrown into reverse, and ATP can be hydrolysed to provide the energy to pump protons against an electrochemical gradient.
This protein is fundamental to living things. A person makes and recycles roughly their body weight in ATP every day.