Importance of the phosphocholine linkage on sphingomyelin molecular properties and interactions with cholesterol; a study with phosphate oxygen modified sphingomyelin-analogues |
| |
Authors: | Anders Bjö rkbom,Tetsuya Yamamoto,Shuji Harada,J. Peter Slotte |
| |
Affiliation: | a Department of Biochemistry and Pharmacy, Åbo Akademi University, Tykistökatu 6 A, FIN-20520 Turku, Finland b School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda City, Hyogo 669-1337, Japan |
| |
Abstract: | We have characterized the molecular properties and membrane behavior of synthetically modified sphingomyelin analogues, modified on the oxygen connecting the phosphocholine group to the ceramide backbone. The oxygen was replaced with an S-atom (S-PSM), an NH-group (NH-PSM) or a CH2-group (CH2-PSM). Diphenylhexatriene and Laurdan anisotropy experiments showed that an S-linkage increased and NH- and CH2-linkages decreased the stability of PSM-analogue bilayer membranes as compared to PSM. When the polarity of the interface was probed using Laurdan, S-PSM appeared to have a lower polarity as compared to PSM whereas NH-PSM and CH2-PSM had higher polarities of their respective interfaces. Fluorescence quenching-studies with cholestatrienol showed that all compounds formed SM/cholesterol-rich domains. The S-PSM/cholesterol and PSM/cholesterol domains displayed a similar thermostability, whereas NH-PSM/cholesterol and CH2-PSM/cholesterol domains were less thermostable. DSC on vesicles containing the PSM-analogues showed a more complex melting behavior as compared to PSM, whereas equimolar mixtures of the PSM-analogues and PSM showed almost ideal mixing with PSM for NH- and S-PSM. Our data show that the properties of the bond linking the phosphocholine head group to the 1-hydroxyl on the ceramide molecule is important for the stability of SM/SM and SM/cholesterol interactions. |
| |
Keywords: | 7SLPC, 1-palmitoyl-2-stearoyl-(7-DOXYL)-sn-glycero-3-phosphocholine CH2-PSM, PSM with its proximal esteric oxygen replaced with a CH2-group CTL, cholesta-5,7,9(11)-trien-3-beta-ol DHSM, smallcaps" >d-erythro-N-palmitoyl-dihydrosphingomyelin DPH, 1,6-diphenyl-1,3,5-hexatriene DSC, differential scanning calorimetry GP, generalized polarization Laurdan, 6-lauroyl-2-(N,N-dimethylamino)naphthalene ld, liquid disordered-phase lo, liquid ordered-phase NH-PSM, PSM with its proximal esteric oxygen replaced with an NH-group PCPE, N-palmitoyl ceramide phosphoethanolamine POPC, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine PSM, smallcaps" >d-erythro-N-palmitoyl-sphingomyelin SM, sphingomyelin S-PSM, PSM with its proximal esteric oxygen replaced with a S-atom Tm, mid temperature of the transition between gel and ld-phase |
本文献已被 ScienceDirect 等数据库收录! |
|