Conserved extracellular cysteine residues and cytoplasmic loop-loop interplay are required for functionality of the heptahelical MLO protein.

ABSTRACT: We performed a structure-function analysis of the plasma membrane-localized plant-specific barley (Hordeum vulgare) MLO (powdery-mildew-resistance gene o) protein. Invariant cysteine and proline residues, located either in extracellular loops or transmembrane domains that have been conserved in MLO proteins for more than 400 million years, were found to be essential for MLO functionality and/or stability. Similarly to many metazoan G-protein-coupled receptors known to function as homo- and hetero-oligomers, FRET (fluorescence resonance energy transfer) analysis revealed evidence for in planta MLO dimerization/oligomerization. Domain-swap experiments with closely related wheat and rice as well as diverged Arabidopsis MLO isoforms demonstrated that the identity of the C-terminal cytoplasmic

SUBMITTER: Elliott C 

PROVIDER: S-EPMC1134693 | biostudies-literature | 2005 Jan

REPOSITORIES: biostudies-literature