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Giant Vesicles from 72‐Membered Macrocyclic Archæal Phospholipid Analogues: Initiation of Vesicle Formation by Molecular Recognition between Membrane Components
Author(s) -
Eguchi Tadashi,
Arakawa Kenji,
Kakinuma Katsumi,
Rapp Gert,
Ghosh Sangita,
Nakatani Yoichi,
Ourisson Guy
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000915)6:18<3351::aid-chem3351>3.0.co;2-4
Subject(s) - vesicle , chemistry , sulfolobus acidocaldarius , phospholipid , crystallography , bilayer , stereochemistry , membrane , biochemistry , archaea , gene
Abstract Stereochemically pure archæal acyclic bola‐amphiphilic diphosphates 4 and 5 , with the basic structure of the phospholipids found in Sulfolobus , have been synthesized for the first time. The self‐assembly properties have been compared with those of the nearly identical 72‐membered macrocyclic tetraether phosphates 3 a and 3 b , analogues of the major phospholipid components of Sulfolobus, Thermoplasma , and methanogenic Archæa, which were also synthesized. Phase contrast and fluorescence microscopies have shown that the dipolar lipids 1 and 2 spontaneously formed vesicles. Whereas the macrocyclic dipolar phosphates 3 spontaneously formed vesicles (phase contrast and fluorescence microscopies), the bolaform phosphate 4 gave only a lamellar structure (synchrotron diffraction pattern: repeat distance of about 4.25 nm but with only a few layers). However, upon addition of the unphosphorylated precursors phytanol, phytol, or geranylgeraniol to the acyclic lipids 4 and 5 , giant vesicles were rapidly formed. Addition of n ‐hexadecanol or cholesterol did not lead to vesicle formation. Therefore it was concluded that this vesicle formation occurs only when the added molecule is closely compatible with the constituents of the lipid layer and can be inserted into the double layer. A slight mismatch (cholesterol or n ‐hexadecanol/polyprenyl chains) is therefore enough to block the insertion process presumably required for vesicle formation.