Protonation of palmitic acid embedded in DPPC lipid bilayers obscures detection of ripple phase by FTIR spectroscopy

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F24%3A43930797" target="_blank" >RIV/60461373:22340/24:43930797 - isvavai.cz</a>

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S1386142524009399?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S1386142524009399?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.saa.2024.124773" target="_blank" >10.1016/j.saa.2024.124773</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Protonation of palmitic acid embedded in DPPC lipid bilayers obscures detection of ripple phase by FTIR spectroscopy

Popis výsledku v původním jazyce

The transformation of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers from the gel (Lβ′) to the fluid (Lα) phase involves an intermediate ripple (Pβ′) phase forming a few degrees below the main transition temperature (Tm). While the exact cause of bilayer rippling is still debated, the presence of amphiphilic molecules, pH, and lipid bilayer architecture are all known to influence (pre)transition behavior. In particular, fatty acid chains interact with hydrophobic lipid tails, while the carboxylic groups simultaneously participate in proton transfer with interfacial water in the polar lipid region which is controlled by the pH of the surrounding aqueous medium. The molecular-level variations in the DPPC ripple phase in the presence of 2% palmitic acid (PA) were studied at pH levels 4.0, 7.3, and 9.1, where PA is fully protonated, partially protonated, or fully deprotonated. Bilayer thermotropic behavior was investigated by differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR) spectroscopy which agreed in their characterization of (pre)transition at pH of 9.1, but not at pH 4.0 and especially not at 7.3. Owing to the different insertion depths of protonated and deprotonated PA, along with the ability of protonated PA to undergo flip-flop in the bilayer, these two forms of PA show a different hydration pattern in the interfacial water layer. Finally, these results demonstrated the hitherto undiscovered potential of FTIR spectroscopy in the detection of the events occurring at the surface of lipid bilayers that obscure the low-cooperativity phase transition explored in this work. © 2024 Elsevier B.V.

Název v anglickém jazyce

Protonation of palmitic acid embedded in DPPC lipid bilayers obscures detection of ripple phase by FTIR spectroscopy

Popis výsledku anglicky

The transformation of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid bilayers from the gel (Lβ′) to the fluid (Lα) phase involves an intermediate ripple (Pβ′) phase forming a few degrees below the main transition temperature (Tm). While the exact cause of bilayer rippling is still debated, the presence of amphiphilic molecules, pH, and lipid bilayer architecture are all known to influence (pre)transition behavior. In particular, fatty acid chains interact with hydrophobic lipid tails, while the carboxylic groups simultaneously participate in proton transfer with interfacial water in the polar lipid region which is controlled by the pH of the surrounding aqueous medium. The molecular-level variations in the DPPC ripple phase in the presence of 2% palmitic acid (PA) were studied at pH levels 4.0, 7.3, and 9.1, where PA is fully protonated, partially protonated, or fully deprotonated. Bilayer thermotropic behavior was investigated by differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR) spectroscopy which agreed in their characterization of (pre)transition at pH of 9.1, but not at pH 4.0 and especially not at 7.3. Owing to the different insertion depths of protonated and deprotonated PA, along with the ability of protonated PA to undergo flip-flop in the bilayer, these two forms of PA show a different hydration pattern in the interfacial water layer. Finally, these results demonstrated the hitherto undiscovered potential of FTIR spectroscopy in the detection of the events occurring at the surface of lipid bilayers that obscure the low-cooperativity phase transition explored in this work. © 2024 Elsevier B.V.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10403 - Physical chemistry

Projekt

—

Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY

ISSN

1386-1425

e-ISSN

1873-3557

Svazek periodika

322

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

11

Strana od-do

—

Kód UT WoS článku

001269444500001

EID výsledku v databázi Scopus

2-s2.0-85198056453