Plant Biol (Stuttg) 1999; 1(6): 638-644
DOI: 10.1055/s-2007-978567
Original Papers

© Georg Thieme Verlag Stuttgart · New York

Cloning and Characterization of Cystathionine γ-Synthase from Solanum tuberosum L.*

K. Riedel1 , C. Mangelsdorf1 , W. Streber2 , L. Willmitzer1 , R. Höfgen1 , H. Hesse3
  • 1Max-Planck-Institut für Molekulare Pflanzenphysiologie, Golm, Germany
  • 2AgrEvo, Forschung Biochemie, Frankfurt am Main, Germany
  • 3Institut für Biologie, Angewandte Genetik, Freie Universität Berlin, Germany
* The nucleotide sequence data reported will appear in the EMBL Data-base under the accession number AF082891.
Further Information

Publication History

1999

1999

Publication Date:
19 April 2007 (online)

Abstract

The first step of methionine biosynthesis in higher plants, the condensation of O-phosphohomoserine and L-cysteine forming the thioether Cystathionine, is catalyzed by the enzyme Cystathionine γ-synthase (CgS). We have isolated a cDNA encoding CgS from a leaf λ ZAP II-library of Solanum tuberosum L. The nucleotide and deduced amino acid sequence showed homology to the other CgS sequences from Arabidopsis thaliana, Zea mays, Mesembryanthemum crystallinum and Fragaria vesca. The truncated cDNA without putative leader peptide, when cloned into a bacterial expression vector, complemented the E. coli metB1 mutant strain LE392. Enzyme activity of the potato CgS and E. coli metB were comparable in the auxotrophic background. Transcript levels of CgS in different tissues of potato plants were determined by Northern blot analysis. Expression was found in all tissues with elevated levels in flowers and source leaves. The pattern of gene expression during a day/night period implied light-dependent control of CgS transcription typical for enzymes localized in plastids. The expression of CgS was shown to be light-inducible.

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