Hydroxycholesterol-25 interacts differently with lipids of the inner and outer membrane leaflet-The Langmuir monolayer study complemented with theoretical calculations was written by Wnetrzak, Anita;Chachaj-Brekiesz, Anna;Kus, Karolina;Filiczkowska, Anna;Lipiec, Ewelina;Kobierski, Jan;Petelska, Aneta D.;Dynarowicz-Latka, Patrycja. And the article was included in Journal of Steroid Biochemistry and Molecular Biology in 2021.Name: (2R)-3-(((2-Aminoethoxy)(hydroxy)phosphoryl)oxy)propane-1,2-diyl dipalmitate The following contents are mentioned in the article:
25-Hydroxycholesterol (25-OH), a mol. with unusual behavior at the air/water interface, being anchored to the water surface alternatively with a hydroxyl group at C(3) or C(25), has been investigated in mixtures with main membrane phospholipids (phosphatidylcholines – PCs, and phosphatidylethanolamines – PEs), characteristic of the outer and inner membrane leaflet, resp. To achieve this goal, the classical Langmuir monolayer approach based on thermodn. anal. of interactions was conducted in addition to microscopic imaging of films (in situ with BAM and after transfer onto mica with AFM), surface-sensitive spectroscopy (PM-IRRAS), as well as theor. calculations Our results show that the strength of interactions is primarily determined by the kind of polar group (strong, attractive interactions leading to surface complexes formation were found to occur with PCs while weak or repulsive ones with PEs). Subsequently, the saturation of phosphatidylcholines apolar chain(s) was found to be crucial for the structure of the formed complexes. Namely, saturated PC (DPPC) does not have preferences regarding the orientation of 25-OH mol. in surface complexes (which results in the two possible 25-OH arrangements), while unsaturated PC (DOPC) enforces one specific orientation of oxysterol (with C(3)-OH group). Our findings suggest that the transport of 25-OH between inner and outer membrane leaflet can proceed without orientation changes, which is thermodynamically advantageous. This explains results found in real systems showing significant differences in the rate of transmembrane transport of 25-OH and the other chain-oxidized oxysterols compared to their ring-oxidized analogs or cholesterol. This study involved multiple reactions and reactants, such as (2R)-3-(((2-Aminoethoxy)(hydroxy)phosphoryl)oxy)propane-1,2-diyl dipalmitate (cas: 923-61-5Name: (2R)-3-(((2-Aminoethoxy)(hydroxy)phosphoryl)oxy)propane-1,2-diyl dipalmitate).
(2R)-3-(((2-Aminoethoxy)(hydroxy)phosphoryl)oxy)propane-1,2-diyl dipalmitate (cas: 923-61-5) belongs to alcohols. A strong base can deprotonate an alcohol to yield an alkoxide ion (R―O−). For example, sodamide (NaNH2), a very strong base, abstracts the hydrogen atom of an alcohol. Secondary alcohols are easily oxidized without breaking carbon-carbon bonds only as far as the ketone stage. No further oxidation is seen except under very stringent conditions.Name: (2R)-3-(((2-Aminoethoxy)(hydroxy)phosphoryl)oxy)propane-1,2-diyl dipalmitate
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