3b86
From Proteopedia
Crystal structure of T57S substituted LUSH protein complexed with ethanol
Structural highlights
Function[OB76A_DROME] Odorant-binding protein required for olfactory behavior and for activity of pheromone-sensitive neurons. Binds to alcohols and mediates avoidance behavior to high concentrations of alcohols, the alcohol-binding possibly resulting in activation of receptors on T2B neurons, the activation of these receptors inhibiting these neurons. Acts in concert with Snmp and lush to capture cVA molecules on the surface of Or67d expressing olfactory dendrites and facilitate their transfer to the odorant-receptor Orco complex. Required for cVA response, probably by binding to VA. May act by serving as an adapter that bridges the presence of gaseous pheromone molecules, cVA, to activation of specific neuronal receptors expressed on T1 olfactory neurons, possibly via a specific conformational change induced by cVA that in turn activates T1 receptors. T1 neurons are excited by the pheromone VA, while T2 neurons are inhibited by alcohols. Also binds to phthalates.[1] [2] [3] [4] [5] [6] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIt is now generally accepted that many of the physiological effects of alcohol consumption are a direct result of binding to specific sites in neuronal proteins such as ion channels or other components of neuronal signaling cascades. Binding to these targets generally occurs in water-filled pockets and leads to alterations in protein structure and dynamics. However, the precise interactions required to confer alcohol sensitivity to a particular protein remain undefined. Using information from the previously solved crystal structures of the Drosophila melanogaster protein LUSH in complexes with short-chain alcohols, we have designed and tested the effects of specific amino acid substitutions on alcohol binding. The effects of these substitutions, specifically S52A, T57S, and T57A, were examined using a combination of molecular dynamics, X-ray crystallography, fluorescence spectroscopy, and thermal unfolding. These studies reveal that the binding of ethanol is highly sensitive to small changes in the composition of the alcohol binding site. We find that T57 is the most critical residue for binding alcohols; the T57A substitution completely abolishes binding, while the T57S substitution differentially affects ethanol binding compared to longer-chain alcohols. The additional requirement for a potential hydrogen-bond acceptor at position 52 suggests that both the presence of multiple hydrogen-bonding groups and the identity of the hydrogen-bonding residues are critical for defining an ethanol binding site. These results provide new insights into the detailed chemistry of alcohol's interactions with proteins. The role of multiple hydrogen-bonding groups in specific alcohol binding sites in proteins: insights from structural studies of LUSH.,Thode AB, Kruse SW, Nix JC, Jones DN J Mol Biol. 2008 Mar 7;376(5):1360-76. Epub 2008 Jan 5. PMID:18234222[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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