FRET Detects the Size of Nanodomains for Coexisting Liquid-Disordered and Liquid-Ordered Phases

Autor(es)

Enoki, Thais A. ^[1] ; Heberle, Frederick A. ^{[2, 3]} ; Feigenson, Gerald W. ^[1]

Afiliação do(s) autor(es)

^[1] Cornell Univ, Dept Mol Biol & Genet, Ithaca, NY 14850 - USA

^[2] Oak Ridge Natl Lab, Joint Inst Biol Sci, Oak Ridge, TN - USA

^[3] Oak Ridge Natl Lab, Neutron Sci Directorate, Large Scale Struct Grp, Oak Ridge, TN - USA

• Tipo de documento: Artigo Científico
• Fonte: BIOPHYSICAL JOURNAL; v. 114, n. 8, p. 1921-1935, APR 24 2018.
• Citações Web of Science: 5

Resumo

Biomembranes with as few as three lipid components can form coexisting liquid-disordered (Ld) and liquid-ordered (Lo) phases. In the coexistence region of Ld and Lo phases, the lipid mixtures 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/chol or brain sphingomyelin (bSM)/DOPC/chol form micron-scale domains that are easily visualized with light microscopy. Although large domains are not observed in the mixtures DSPC/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/chol and bSM/POPC/chol, lateral heterogeneity is nevertheless detected using techniques with nanometer-scale spatial resolution. We propose a simple and accessible method to measure domain sizes below optical resolution (similar to 200 nm). We measured nanodomain size for the latter two mixtures by combining experimental Forster resonance energy transfer data with a Monte-Carlo-based analysis. We found a domain radius of 7.5-10 nm for DSPC/POPC/chol, similar to values obtained previously by neutron scattering, and similar to 5 nm for bSM/POPC/chol, slightly smaller than measurable by neutron scattering. These analyses also detect the domain-size transition that is observed by fluorescence microscopy in the four-component lipid mixture bSM/DOPC/POPC/chol. Accurate measurements of fluorescent-probe partition coefficients are especially important for the analysis; therefore, we exploit three different methods to measure the partition coefficient of fluorescent molecules between Ld and Lo phases. (AU)

• Processo FAPESP: 13/00473-6 - Interação de peptídeos antimicrobianos em membranas modelos com coexistência de domínios lipídicos
• Beneficiário: Thais Azevedo Enoki Liarte
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado