Archives of Microbiology

, Volume 168, Issue 5, pp 421–427

The path of unspecific incorporation of selenium in Escherichia coli

  • Sabine Müller
  • Johann Heider
  • A. Böck
Original paper

DOI: 10.1007/s002030050517

Cite this article as:
Müller, S., Heider, J. & Böck, A. Arch Microbiol (1997) 168: 421. doi:10.1007/s002030050517
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Abstract

The path of unspecific selenium incorporation into proteins was studied in Escherichia coli mutants blocked in the biosynthesis of cysteine and methionine or altered in its regulation. Selenium incorporation required all enzymatic steps of cysteine biosynthesis except sulfite reduction, indicating that intracellular reduction of selenite occurs nonenzymatically. Cysteine (but not methionine) supplementation prevented unspecific incorporation of selenium by repressing cysteine biosynthesis. On the other hand, when the biosynthesis of cysteine was derepressed in regulatory mutants, selenium was incorporated to high levels. These findings and the fact that methionine auxotrophic strains still displayed unspecific incorporation show that selenium incorporation into proteins in E. coli occurs mainly as selenocysteine. These findings also provide information on the labeling conditions for incorporating 75Se only and specifically into selenoproteins.

Key wordsEscherichia coli Selenoproteins Selenocysteine Selenomethionine Monoselenophosphate synthetase Cysteine biosynthesis 

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Sabine Müller
    • 1
  • Johann Heider
    • 2
  • A. Böck
    • 1
  1. 1.Lehrstuhl für Mikrobiologie, Universität München, Maria-Ward-Strasse 1a, D-80638 München, Germany Tel. +49-89-17919856; Fax +49-89-17919862 e-mail: august.boeck@lrz.uni-muenchen.deDE
  2. 2.Institut für Biologie II/Mikrobiologie, Universität Freiburg, Schänzlestrasse 1, D-79104 Freiburg, GermanyDE

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