Phytoene synthase from Narcissus pseudonarcissus: Functional expression, galactolipid requirement, topological distribution in chromoplasts and induction during flowering

Michael Schledz, Salim Al-Babili, Johannes V. Lintig, Heinz Haubruck, Said Rabbani, Hans Kleinig, Peter Beyer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

88 Scopus citations

Abstract

A cDNA coding for the carotenoid biosynthetic enzyme phytoene synthase was cloned from a Narcissus pseudonarcissus flower cDNA library, and the corresponding protein was overexpressed in insect cells using the baculovirus lipofection system. The full-length overexpressed enzyme exhibited very reduced catalytic activity compared with an overexpressed N-truncated form, with its transit sequence removed by site-directed mutagenesis. The shortened form readily bound quantitatively to lipid bilayers. Although it was active with liposomes prepared from plastid lipids, with phospholipid liposomes it was not, even though association took place. In this latter case, free galactose was capable of substituting for galactolipids, resulting in enzymatic activity. It is concluded that galactolipids are involved in catalytic activity, but do not serve as a membrane anchor. Antibodies raised against the recombinant enzyme made it possible to distinguish between a membrane-bound and a soluble, protein-complexed inactive form of phytoene synthase, present in the chromoplast stroma. These findings and data on phytoene synthase mRNA and protein expression presented here are discussed in terms of a possible regulatory role in color formation during chromoplast (flower) development.

Original languageEnglish (US)
Pages (from-to)781-792
Number of pages12
JournalPlant Journal
Volume10
Issue number5
DOIs
StatePublished - Nov 1 1996

ASJC Scopus subject areas

  • Genetics
  • Plant Science
  • Cell Biology

Cite this