Complexation and evolution of cis‐prenyltransferase homologues in Cinnamomum kanehirae deduced from kinetic and functional characterizations

Eukaryotic dehydrodolichyl diphosphate synthases (DHDDSs), cis‐prenyltransferases (cis‐PTs) synthesizing precursors of dolichols to mediate glycoprotein biosynthesis require partners, for eample Nus1 in yeast and NgBR in animals, which are cis‐PTs homologues without activity but to boost the DHDDSs activity. Unlike animals, plants have multiple cis‐PT homologues to pair or stand alone to produce various chain‐length products with less known physiological roles. We chose Cinnamomum kanehirae, a tree that contains two DHDDS‐like and three NgBR‐like proteins from genome analysis, and found that one DHDDS‐like protein acted as a homodimeric cis‐PT to make a medium‐chain C55 product, while the other formed heterodimeric complexes with either one of two NgBR homologues to produce longer‐chain products. Both complexes were functional to complement the growth defect of the yeast rer2 deficient strain at a higher temperature. From the roles for the polyprenol and dolichol biosynthesis and sequence motifs, their homologues in various species were compared to reveal their possible evolutionary paths.