The terminal O‐acetyltransferase involved in vindoline biosynthesis defines a new class of proteins responsible for coenzyme A‐dependent acyl transfer

Plant Journal - Tập 14 Số 6 - Trang 703-713 - 1998
Benoit St‐Pierre1, Pierre Laflamme1, Anne‐Marie Alarco1,2, Di Marzo Vincenzo1, EVA DE LUCA1
1Institut de recherche en Biologie Végétale, Département de Sciences Biologiques, Université de Montréal, 4101 Rue Sherbrooke Est, Montréal, Québec, Canada H1X 2B2
2†Present address: Institut de Recherches Cliniques de Montréal, 110 Ave. Des Pins Ouest, Montréal, Québec, Canada H21 4M1.

Tóm tắt

SummaryThe gene encoding acetyl CoA:deacetylvindoline 4‐O‐acetyltransferase (DAT) (EC 2.3.1.107) which catalyzes the last step in vindoline biosynthesis was isolated and characterized. The genomic clone encoded a 50 kDa polypeptide containing the sequences of nine tryptic fragments derived from the purified DAT heterodimer. However, cleavage of DAT protein to yield a heterodimer appears to be an artifact of the protein purification procedure, since the size of the protein (50 kDa) cross‐reacting with anti‐DAT antibody in seedlings and in leaves of various ages also corresponds to the size of the active recombinant enzyme. Studies with the intact plant and with developing seedlings showed that induction of DAT mRNA, protein accumulation and enzyme activity occurred preferentially in vindoline producing tissues such as leaves and cotyledons of light‐treated etiolated seedlings. The ORF of DAT showed significant sequence identity to 19 other plant genes, whose biochemical functions were mostly unknown. The Mr of ≈ 50 kDa, a HXXXDG triad, and a DFGWGKP consensus sequence are highly conserved among the 20 plant genes and these criteria may be useful to identify this type of acyltransferase. The involvement of some of these genes in epicuticular wax biosynthesis, fruit‐ripening and in benzoyltransfer reactions indicates that the plant kingdom contains a superfamily of multifunctional acyltransferases which operate by a reaction mechanism related to the ancient chloramphenicol O‐acetyltransferase and dihydrolipoyl acetyltransferase class of enzymes.

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Plant Journal

Tập 14 Số 6

703-713

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