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Functional reconstitution of β‐glucan elicitor‐binding activity upon incorporation into lipid vesicles
Author(s) -
Mithöfer Axel,
Ebel Jürgen
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01126-6
Subject(s) - glucan , chemistry , vesicle , membrane , elicitor , biochemistry , binding site , ligand (biochemistry) , binding protein , biophysics , receptor , biology , enzyme , gene
In temperature‐induced Triton X‐114 phase separation experiments the β‐glucan elicitor‐binding site from soybean ( Glycine max L.) root membranes was identified as (a) hydrophobic membrane protein(s). The Zwittergent 3‐12‐solubilized β‐glucan‐binding proteins were incorporated into lipid vesicles by the detergent‐dilution procedure. Reconstituted binding proteins were functional in that binding of the hepta‐β‐glucoside ligand was saturable, reversible and of high affinity ( K d =6–7 nM). Competition studies using β‐glucans with different degrees of polymerization (DP 7–15; DP 15–25) showed effective displacement of the radioligand from the binding site whereas β‐glucan fragments with DP <7 were ineffective. The total amount of reconstituted binding activity was dependent on the acyl chain length of the phospholipids used for the reconstitution with a preference for decanoic (C10) and dodecanoic (C12) chains. Restored ligand binding was maximally 37% as compared to the former detergent‐solubilized binding activity. The presence of a lipid environment stabilized the purified β‐glucan‐binding proteins.