Refractive-Index-Based Screening of Membrane-Protein-Mediated Transfer across Biological Membranes
Artikel i vetenskaplig tidskrift, 2010

Numerous membrane-transport proteins are major drug targets, and therefore a key ingredient in pharmaceutical development is the availability of reliable, efficient tools for membrane transport characterization and inhibition. Here, we present the use of evanescent-wave sensing for screening of membrane-protein-mediated transport across lipid bilayer membranes. This method is based on a direct recording of the temporal variations in the refractive index that occur upon a transfer-dependent change in the solute concentration inside liposomes associated to a surface plasmon resonance (SPR) active sensor surface. The applicability of the method is demonstrated by a functional study of the aquaglyceroporin PfAQP from the malaria parasite Plasmodium falciparum. Assays of the temperature dependence of facilitated diffusion of sugar alcohols on a single set of PfAQP-reconstituted liposomes reveal that the activation energies for facilitated diffusion of xylitol and sorbitol are the same as that previously measured for glycerol transport in the aquaglyceroporin of Escherichia coli (5 kcal/mole). These findings indicate that the aquaglyceroporin selectivity filter does not discriminate sugar alcohols based on their length, and that the extra energy cost of dehydration of larger sugar alcohols, upon entering the pore, is compensated for by additional hydrogen-bond interactions within the aquaglyceroporin pore.

escherichia-coli

permeability

aquaglyceroporin glpf

solution exchange

falciparum

light-scattering

surface-plasmon resonance

coli glycerol facilitator

liposome membranes

transport

Författare

Magnus Brändén

Chalmers, Teknisk fysik, Biologisk fysik

Seyed Tabaei

Chalmers, Teknisk fysik, Biologisk fysik

Gerhard Fischer

Göteborgs universitet

Richard Neutze

Göteborgs universitet

Fredrik Höök

Chalmers, Teknisk fysik, Biologisk fysik

Biophysical Journal

0006-3495 (ISSN) 1542-0086 (eISSN)

Vol. 99 124-133

Ämneskategorier

Annan teknik

DOI

10.1016/j.bpj.2010.03.059