Partition of amphiphilic molecules to lipid bilayers by isothermal titration calorimetry

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Maria Joao Moreno (Author) Other; Margarida Bastos (Author) FCUP; Adrian Velazquez Campoy (Author) Other

Journal

Title: Analytical Biochemistry

Vol. 399

Pages: 44-47

ISSN: 0003-2697

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 26 Citations

Scopus - 26 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

CORDIS: Physical sciences > Chemistry > Applied chemistry ; Physical sciences > Chemistry > Physical chemistry

Other information

Authenticus ID: P-003-7M4

DOI: 10.1016/j.ab.2009.11.015

Abstract (EN): The partition of the amphiphile sodium dodecyl sulfate (SDS) between an aqueous solution and a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer was followed by isothermal titration calorimetry (ITC) as a function of the total concentration of SDS. It was found that the obtained partition coefficient is strongly affected by the ligand concentration, even after correction for the charge imposed in the bilayer by the bound SDS. The partition coefficient decreased as the total concentration of SDS increased, with this effect being significant for local concentrations of SDS in the lipid bilayer above 5 molar%. At those high local concentrations, the properties of the lipid bilayer are strongly affected, leading to nonideal behavior and concentration-dependent apparent partition coefficients. It is shown that with the modern ITC instruments available, the concentrations of SDS can be drastically reduced while maintaining a good signal-to-noise ratio. The intrinsic parameters of the interaction with unperturbed membranes can be obtained from the asymptotic behavior of the apparent parameters as a function of the ligand concentration for both nonionic and ionic solutes. A detailed analysis is performed, and a spreadsheet is provided to obtain the interaction parameters with and without correction for electrostatics.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4