Burning fat: the structural basis of fatty acid beta-oxidation

Recent advances in the structural biology of the enzymes involved in fatty acid oxidation have revealed their catalytic mechanisms and modes of substrate binding. Although these enzymes all use coenzyme A (CoA) thioesters as substrates, they share no common polypeptide folding topology or CoA-binding motif. Each family adopts an entirely unique protein fold. Their mode of binding the CoA thioester is similar in that the fatty-acyl moiety is buried inside the protein and the nucleotide portion is mainly exposed to solvent; however, the conformations of the enzyme-bound CoA ligands vary considerably. Furthermore, a comparison of these structures suggests a structural basis for the broad substrate chain length specificity that is a unique feature of these enzymes.