Crotonase folds

The active site of enoyl-CoA isomerase is a good example of an active site built on the framework of the crotonase fold. It is now weU established that this crotonase fold provides an active site framework that has been used by Nature for a wide range of different chemical reactions, as reviewed recently [73, 85]. The reaction of this enoyl-CoA isomerase is initiated by a catalytic base, Glul36, abstracting a proton from the Ca-carbon, generating the negatively charged enolate... 

The oxoester analog of crotonyl-CoA 26 shown in Fig. 5 was used as an alternative substrate for crotonase and exhibited about 300-fold decreased activity relative to the natural... 

In discussions on the mechanisms of the enzymes involved in each pathway, there will be a particular focus on three superfamilies enzymes that share the thiolase fold and catalyze carbon—carbon bond formation and cleavage reactions catalyzed by NAD(P)-dependent enzymes in the fatty acid biosynthesis pathway involve proteins that are members of the short-chain dehydrogenase reductase (SDR) superfamily and finally there are mechanistic parallels between the hydration and dehydration reactions in each pathway with a particular focus on the crotonase superfamily. 

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