Selective Organization of an alpha-Helical Hydrophobic Polypeptide/Pigment Complex in a Lipid Domain of Binary Lipid Bilayers

被引:3
|
作者
Dewa, Takehisa [1 ,2 ]
Yoshida, Kiyotaka [1 ]
Sugimoto, Miku [1 ]
Sugiura, Ryuta [1 ]
Nango, Mamoru [1 ]
机构
[1] Nagoya Inst Technol, Mat Sci & Engn, Showa Ku, Gokiso Cho, Nagoya, Aichi 4668555, Japan
[2] JST, PRESTO, Kawaguchi, Saitama, Japan
来源
E-JOURNAL OF SURFACE SCIENCE AND NANOTECHNOLOGY | 2005年 / 3卷
基金
日本科学技术振兴机构;
关键词
Biological molecules-proteins; Lipid domain; Membrane protein complex; FRET;
D O I
10.1380/ejssnt.2005.145
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
We present here a novel approach to organization of an alpha-helical hydrophobic polypeptide complex in lipid bilayers in a 'lipid-domain-selective' manner. The key strategy is to use disulfide linkage between a cysteine-bearing polypeptide and a disulfide-based phospholipid, the latter of which forms a phase-separated lipid domain in a binary lipid bilayer with an incompatible phospholipid lacking disulfide group. The cross-linkage between the polypeptide and the phospholipid can be expected that the polypeptide acquires a higher affinity to the disulfide-based lipid domain than to the other one, resulting in selective distribution of the polypeptide in the former domain. The polypeptide analogous to a photosynthetic bacterial light-harvesting polypeptide binds a pigment, zinc-substituted bacteriochlorophyll a ([Zn]-BChl alpha), to form the light-harvesting polypeptide/pigment complex. The complex was incorporated into an incompatible binary lipid bilayer combination either the disulfide-based phospholipids bearing oleoyl chains (DO-DO)/1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) or 1,2-dioleoylsn-glycero-3-phosphocholine (DOPC)/DSPC. The lipid-domain-selective organization was confirmed by fluorescence resonance energy transfer (FRET) from a rhodamine-labeled lipid (Lissamine rhodamine B 1,2-diacyl-snglycero-3-phosphoethanolamine: either N-Rh-DOPE or N-Rh-DSPE) to the assembled [Zn]-BChl alpha. Considering the relative affinity of these fluorescent lipid probes, N-Rh-DOPE and N-Rh-DSPE prefer to fluid and gel domains, respectively, because of the similarity of their acyl chains. When the fluorescent lipid probe, N-Rh-DOPE, was applied to the binary lipid system, DO-DO/DSPC, the higher FRET efficiency was observed compared to the counterpart FRET assay using N-Rh-DSPE. In contrast, for the DOPC/DSPC bilayer, the difference in the FRET efficiency between the fluorescent lipid probe systems was negligible. These results suggest that the polypeptide/pigment complex is preferentially incorporated into the disulfide-based lipid domain. Total internal reflection fluorescence (TIRF) microscopic observation of the assembly also evidenced heterogeneous structure by detection of fluorescence from [Zn]-BChl alpha.
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页码:145 / 150
页数:6
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