PubMed · 2026-05-23
Scientists solved the 3D structure of a plant immune protein found in flower nectar — and discovered it looks and behaves nothing like its pathogen-fighting cousins, suggesting it has an entirely different, still-unknown job in the plant.
The protein MsPR-1b forms a homodimer (two identical units paired together) — the first native PR-1 protein ever crystallized directly from its natural plant source, resolved at 2.0 Å resolution.
Despite belonging to a protein family associated with immune defense, MsPR-1b shows no detectable lipid-binding ability and no direct antimicrobial activity.
The protein is expressed almost exclusively in the nectary (nectar-producing tissue), is not glycosylated, and has a basic character (pI 9.4, 15,134 Da), distinguishing it from typical acidic defense-related PR-1 proteins.
