[The structural and functional characteristics of the dolichol cycle enzymes].

The literature and the authors' our data on the biosynthesis of a dolichol derivative Dol-PP-GlcNAc2Man9Glc3, involved in protein N-glycosylation in the endoplasmic reticulum (ER) of the eukaryotic cells, have been summarized and analysed. The structural and functional characteristics of dolichol-coupled enzymes, catalyzing biosynthesis of Dol-PP-GlcNAc2Man9Glc3, are considered. It is shown that the dolichol cycle enzymes, in conformity with their structural peculiarities and ER membrane topology, can be divided into three groups having the common evolutionary origin. Possible mechanisms of the dolichol derivative translocation through membrane is discussed. A conclusion is made about formation of multicomponent complexes by dolichol-coupled enzymes. These complexes secure functional co-ordination of the enzymes.