- Carbon chain shape selectivity by the mouse olfactory receptor OR-I7
-
The rodent OR-I7 is an olfactory receptor exemplar activated by aliphatic aldehydes such as octanal. Normal alkanals shorter than heptanal bind OR-I7 without activating it and hence function as antagonists in vitro. We report a series of aldehydes designed to probe the structural requirements for aliphatic ligand chains too short to meet the minimum approximate 6.9 ? length requirement for receptor activation. Experiments using recombinant mouse OR-I7 expressed in heterologous cells show that in the context of short aldehyde antagonists, OR-I7 prefers binding aliphatic chains without branches, though a single methyl on carbon-3 is permitted. The receptor can accommodate a surprisingly large number of carbons (e.g. ten in adamantyl) as long as the carbons are part of a conformationally constrained ring system. A rhodopsin-based homology model of mouse OR-I7 docked with the new antagonists suggests that small alkyl branches on the alkyl chain sterically interfere with the hydrophobic residues lining the binding site, but branch carbons can be accommodated when tied back into a compact ring system like the adamantyl and bicyclo[2.2.2]octyl systems.
- Liu, Min Ting,Ho, Jianghai,Liu, Jason Karl,Purakait, Radhanath,Morzan, Uriel N.,Ahmed, Lucky,Batista, Victor S.,Matsunami, Hiroaki,Ryan, Kevin
-
supporting information
p. 2541 - 2548
(2018/04/12)
-
- Synthesis of Ethylenes with Acyclic Quaternary Carbons by Dehydration of Neopentyl Alcohols. Application of the 2-D INAPT Technique
-
Di- and triquaternary ethylenes (5, 12 and 7, 19, Scheme I) have been synthesized by dehydration of sec- and tert-neopentyl alcohols (4, 11 and 6, 18) without rearrangement.It is thought that steric factors determine the structures of the products.The intermediate imines 2 and 14, from the reaction of nitriles 1 and 13 with t-C4H9Li, may be hydrolyzed only in the first case to ketones (3).More highly substituted ketones (10 and 16) were obtained by the reaction of t-RMgX (9) or (CH3)3CMgCl with 3,3-dialkyl and 2,3,3-trialkyl acid chlorides (8 and 15).Ketones 3 and 10 were reduced by LiAlH4 to secondary carbinols 4 and 11.The tertiary carbinols 6 were prepared from 3 by treatment with t-C4H9Li.The more hindered ketones 16 failed to add t-C4H9Li, but were reduced to secondary alcohols 18, instead of the desired tertiary alcohols 17.The carbinols 4, 6, 11, and 18 were dehydrated by heating with KHSO4.The 2-D INAPT NMR technique was used to establish the stereostructure of 19 by measuring the long-range heteronuclear coupling constants about the ene.
- Drake, C. A.,Rabjohn, Norman,Tempesta, Michael S.,Taylor, Richard B.
-
p. 4555 - 4562
(2007/10/02)
-