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Structure of Cockroach Allergen Bla g 1 Tandem Repeat as a EGFP fusion
Structural highlights
FunctionQ9UAM5_BLAGE GFP_AEQVI Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin. Publication Abstract from PubMedBACKGROUND: Sensitization to cockroach allergens is a major risk factor for asthma. The cockroach allergen Bla g 1 has multiple repeats of approximately 100 amino acids, but the fold of the protein and its biological function are unknown. OBJECTIVE: We sought to determine the structure of Bla g 1, investigate the implications for allergic disease, and standardize cockroach exposure assays. METHODS: nBla g 1 and recombinant constructs were compared by using ELISA with specific murine IgG and human IgE. The structure of Bla g 1 was determined by x-ray crystallography. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to examine the ligand-binding properties of the allergen. RESULTS: The structure of an rBla g 1 construct with comparable IgE and IgG reactivity to the natural allergen was solved by x-ray crystallography. The Bla g 1 repeat forms a novel fold with 6 helices. Two repeats encapsulate a large and nearly spherical hydrophobic cavity, defining the basic structural unit. Lipids in the cavity varied depending on the allergen origin. Palmitic, oleic, and stearic acids were associated with nBla g 1 from cockroach frass. One unit of Bla g 1 was equivalent to 104 ng of allergen. CONCLUSIONS: Bla g 1 has a novel fold with a capacity to bind various lipids, which suggests a digestive function associated with nonspecific transport of lipid molecules in cockroaches. Defining the basic structural unit of Bla g 1 facilitates the standardization of assays in absolute units for the assessment of environmental allergen exposure. The novel structure of the cockroach allergen Bla g 1 has implications for allergenicity and exposure assessment.,Mueller GA, Pedersen LC, Lih FB, Glesner J, Moon AF, Chapman MD, Tomer KB, London RE, Pomes A J Allergy Clin Immunol. 2013 Jul 31. pii: S0091-6749(13)00982-2. doi:, 10.1016/j.jaci.2013.06.014. PMID:23915714[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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