2YGU

Crystal structure of fire ant venom allergen, Sol I 2

Summary for 2YGU

• Entry DOI: 10.2210/pdb2ygu/pdb
• Descriptor: VENOM ALLERGEN 2, HEPTANE (3 entities in total)
• Functional Keywords: allergen, hydrophobic cavity, insect odorant binding protein
• Biological source: SOLENOPSIS INVICTA (RED FIRE ANT)
• Cellular location: Secreted: P35775
• Total number of polymer chains: 8
• Total formula weight: 113372.75

Authors

Borer, A.S.,Wassmann, P.,Schirmer, T.,Markovic-Housley, Z. (deposition date: 2011-04-20, release date: 2011-11-23, Last modification date: 2024-11-13)

Primary citation

Borer, A.S.,Wassmann, P.,Schmidt, M.,Hoffman, D.R.,Zhou, J.J.,Wright, C.,Schirmer, T.,Markovic-Housley, Z.
Crystal Structure of Sol I 2, a Major Allergen from Fire Ant Venom
J.Mol.Biol., 415:635-, 2012

PubMed Abstract: Sol i 2 is a potent allergen from the venom of red imported fire ant, which contains allergens Sol i 1, Sol i 2, Sol i 3, and Sol i 4 that are known to be powerful triggers of anaphylaxis. Sol i 2 causes IgE antibody production in about one-third of individuals stung by fire ants. Baculovirus recombinant dimeric Sol i 2 was crystallized as a native and selenomethionyl-derivatized protein, and its structure has been determined by single-wavelength anomalous dispersion at 2.6 Å resolution. The overall fold of each subunit consists of five helices that enclose a central hydrophobic cavity. The structure is stabilized by three intramolecular disulfide bridges and one intermolecular disulfide bridge. The nearest structural homologue is the sequence-unrelated odorant binding protein and pheromone binding protein LUSH of the fruit fly Drosophila, which may suggest a similar biological function. To test this hypothesis, we measured the reversible binding of various pheromones, plant odorants, and other ligands to Sol i 2 by the changes in N-phenyl-1-naphthylamine fluorescence emission upon binding of ligands that compete with N-phenyl-1-naphthylamine. The highest binding affinity was observed for hydrophobic ligands such as aphid alarm pheromone (E)-β-farnesene, analogs of ant alarm pheromones, and plant volatiles decane, undecane, and β-caryophyllene. Conceivably, Sol i 2 may play a role in capturing and/or transporting small hydrophobic ligands such as pheromones, odors, fatty acids, or short-living hydrophobic primers. Molecular surface analysis, in combination with sequence alignment, can explain the serological cross-reactivity observed between some ant species.

PubMed: 22100449
DOI: 10.1016/J.JMB.2011.10.009

Experimental method

X-RAY DIFFRACTION (2.6 Å)