Colipase: structure and interaction with pancreatic lipase

Colipase is a small protein cofactor needed by pancreatic lipase for the ef ficient dietary lipid hydrolysis. It binds to the C-terminal, non-catalytic domain of lipase, thereby stabilising an active conformation and considera bly increasing the overall hydrophobic binding site. Structural studies of the complex and of colipase alone have clearly revealed the functionality o f its architecture. Interestingly, a structural analogy has recently been d iscovered between colipase and a domain in a developmental protein (Dickkop f), based on sequence analogy and homology modeling. Whether this structura l analogy implies a common function (lipid interaction) remains to be clari fied, Structural analogies have also been recognised between the pancreatic lipase C-terminal domain, the N-terminal domains of lipoxygenases and the C-terminal domain of alpha-toxin, These non-catalytic domains in the latter enzymes are important for interaction with membranes. It has not been esta blished if these domains are also involved in eventual protein cofactor bin ding as is the case for pancreatic lipase. (C) 1999 Elsevier Science B.V. A ll rights reserved.