title: NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer: Part III: studies on keto esters and acids.
abstract: The development of "molecular rulers" would allow one to quantitatively locate the penetration depth of intercalants within lipid bilayers. To this end, an attempt was made to correlate the (13)C NMR chemical shift of polarizable "reporter" carbons (e.g., carbonyls) of intercalants within DMPC liposomal bilayers - with the polarity it experiences, and with its Angstrom distance from the interface. This requires families of molecules with two "reporter carbons" separated by a known distance, residing at various depths/polarities within the bilayer. For this purpose, two homologous series of dicarbonyl compounds, methyl n-oxooctadecanoates and the corresponding n-oxooctadecanoic acids (n=4-16), were synthesized. To assist in assignment and detection several homologs in each system were prepared (13)C-enriched in both carbonyls. Within each family, the number of carbons and functional groups remains the same, with the only difference being the location of the second ketone carbonyl along the fatty acid chain. Surprisingly, the head groups within each family are not anchored near the lipid-water interface, nor are they even all located at the same depth. Nevertheless, using an iterative best fit analysis of the data points enables one to obtain an exponential curve. The latter gives substantial insight into the correlation between polarity (measured in terms of the Reichardt polarity parameter, ET(30)) and penetration depth into the liposomal bilayer. Still missing from this curve are data points in the moderate polarity range.
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Michal.Afri@biu.ac.il.
authors: Michal
authors: M
authors: Afri
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: C_Eliasi@walla.com.
authors: Carmit
authors: C
authors: Alexenberg
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Pinchas.Aped@biu.ac.il.
authors: Pinchas
authors: P
authors: Aped
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Efrat.Bodner@biu.ac.il.
authors: Efrat
authors: E
authors: Bodner
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: SaritCohen84@gmail.com.
authors: Sarit
authors: S
authors: Cohen
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: MichalDomb@gmail.com.
authors: Michal
authors: M
authors: Ejgenburg
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: ShlomiEliyohu@gmail.com.
authors: Shlomi
authors: S
authors: Eliyahu
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Pessia.Sharon@biu.ac.il.
authors: Pessia
authors: P
authors: Gilinsky-Sharon
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: IfatAsh@Yahoo.com.
authors: Yifat
authors: Y
authors: Harel
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: MiriamNaqqash@gmail.com.
authors: Miriam E
authors: ME
authors: Naqqash
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: HaniPorat@gmail.com.
authors: Hani
authors: H
authors: Porat
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Ayala.Ranz@gmail.com.
authors: Ayala
authors: A
authors: Ranz
authors: The Department of Chemistry, Bar-Ilan University, Ramat Gan 5290002, Israel. Electronic address: Aryeh.Frimer@biu.ac.il.
authors: Aryeh A
authors: AA
authors: Frimer
mesh_terms: D003998:Dicarboxylic Acids / Q000737:chemistry*; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004952:Esters; D007364:Intercalating Agents / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013816:Thermodynamics
chemical_list: D003998:Dicarboxylic Acids; D004952:Esters; D007364:Intercalating Agents; D008051:Lipid Bilayers; D008081:Liposomes; D004134:Dimyristoylphosphatidylcholine
keywords: (13)C NMR; DMPC; E(T); Liposome; Molecular ruler; Oxooctadecanoates