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Updated: Jul 25, 2026

Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
Tentoxin sensitivity of chloroplasts determined by codon 83 of beta subunit of proton-ATPase
A Avni1, J D Anderson, N Holland
1Department of Plant Genetics, Weizmann Institute of Science, Rehovot, Israel.
Abstract:
Tentoxin is a naturally occurring phytotoxic peptide that causes seedling chlorosis and arrests growth in sensitive plants and algae. In vitro, it inhibits activity of the beta subunit of the plastid proton-adenosine triphosphatase (ATPase) from sensitive species. Plastid atpB genes from six closely related, tentoxin-sensitive or -resistant Nicotiana species differ at codon 83, according to their response to the toxin: glutamate correlated with resistance and aspartate correlated with sensitivity. The genetic relevance of this site was confirmed in Chlamydomonas reinhardtii by chloroplast transformation. The alga, normally tentoxin-resistant, was rendered tentoxin-sensitive by mutagenesis of its plastid atpB gene at codon 83. Codon 83 may represent a critical site on the beta subunit that does not compete with nucleotide binding or other catalytic activities.
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