Lipases evolutionary relationships

Karlsson M, Contreras JA, Heilman U, Tornqvist H, Holm C (1997) cDNA cloning, tissue distribution, and identification of the catalytic triad of monoglyceride lipase. Evolutionary relationship to esterases, lysophospholipases, and haloperoxidases. J Biol Chem 272 27218-27223... 

The earliest observation that implied evolutionary links between all lipases was that of the consensus pentapeptide G-X-S-X-G, subsequently shown to contain the nucleophilic serine. The apparent similarity of this sequence to that found around the active serine in the chy-motrypsin and subtilisin families of serine proteinases prompted a number of authors to infer an evolutionary relationship between the three families. Further evidence in support of such a link came from secondary structure prediction studies indicating that the nucleophilic serine in a lipase is most likely within a /3 turn, structurally reminiscent of proteinases (Reddy et ai, 1986). In fact, one of the commonly used phrases found in introductions to many papers dealing directly or indirectly with lipases refers to the consensus G-X-S-X-G pentapeptide found in the active site of all serine proteinases and esterases. We now know that the implication that homology and/or structural similarities exist between the enzymes belonging to these diverse groups is incorrect. The matter has been dealt with in the literature (Derewenda and Derewenda, 1991 Liao et ai, 1992), but it seems appropriate to review some of the conclusions. 

The jS-eSer-a motif is likely to be present in other enzymes with esterase or thioesterase activity, although their structure may be different from that of the a/jS hydrolases. Some of these proteins have already been crystallized for X-ray studies [e.g.. Vibrio harveyi acyltransferase (Swenson et al., 1992)], and their cryst structures should throw some more light on the structural and evolutionary relationships within the lipase/esterase superfamily. 

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