A Novel Glycolipid and Phospholipid in the Purple Membrane

Abstract

A novel glycolipid of mass 1935 and a phospholipid of mass 1522 are the main residual lipids (along with traces of PGP-Me, S-TGD-1, and PG) specifically associated with "delipidated" bacteriorhodopsin fractions BR I and BR II, prepared by Triton X-100 treatment of purple membrane (PM), from a genetically engineered strain (L33) of Halobacterium salinarum, and chromatography on phenyl-Sepharose CL-4B. The novel glycolipid and phospholipid are components of the PM matrix not previously described. The TLC isolated and purified novel glycolipid and phospholipid were shown, by chemical degradation, mass spectrometry, and NMR analyses, to have the structure, respectively, of a phosphosulfoglycolipid, 3-HSO(3)-Galp-beta1,6Manp-alpha1,2Glcp-alpha1,1-[sn-2, 3-di-O-phytanylglycerol]-6-[phospho-sn-2,3-di-O-phytanylglycero l], and of a glycerol diether analogue of bisphosphatidylglycerol (cardiolipin), sn-2,3-di-O-phytanyl-1-phosphoglycerol-3-phospho-sn-2, 3-di-O-phytanylglycerol.

Enhanced Photocurrent in Engineered Bacteriorhodopsin Monolayer

“…Delipidation, then, occurs with retention of functionality, frees the protein from the confines of rigid twodimensional patches, and facilitates a stable, densely packed chemisorption where a solvent exposed cysteine is present. Though delipidation is expected to occur with retention of approximately one-third of the initial lipid (inside the trimer), 60 the packing density achievable at a solid interface is reflective not only merely of the percentage by volume of sample which is a functional protein but also the effectiveness with which this binds across the surface. We believe, then, that the importance of delipidation lies also within the freedom given to BR trimers to bind effectively across the whole transducing gold surface (the wild type PM patches, due to their rigid "plate" like structure, cannot pack as tightly across the surface; see Figure 2).…”

Recent Advances in Structural Research on Ether Lipids from Archaea Including Comparative and Physiological Aspects

“…The phospholipid is an ether analog of cardiolipin (Fig. 8A), and the phosphoglycolipid is archaetidylated S-TGA-1 42) (Fig. 8B).…”

“…It is interesting that these new lipids have four phytanyl chains in their molecules. Corcelli et al 42) discussed the possible role of these lipids in the energy-transducing apparatus, as in eukaryotic mitochondria. The ether analog of cardiolipin and another phosphoglycolipid which has archaetidylated 6-sulfomannosyl-glucosyl archaeol (archaetidylated S-DGA-1) have also been identified from cells of Haloferax volcanii, which lacks purple membranes 43) ( Fig.…”

“…All these new lipids are composed of a caldarchaeol core, one or two gulose and one to three mannose as sugar moieties, and phosphoglycerol as a phosphodiester-linked polar group in some phosphoglycolipids. In addition, a small amount 42) C, archaetidylated S-DGA-1, viz., 6 0 -sulfoManp-1 0 ,2-(6-archaetidyl)-Glcp-1-archaeol. 43) of diether-type archaetidylglycerol was detected.…”

Natronococcus roseus sp. nov., a haloalkaliphilic archaeon from a hypersaline lake

“…The phenotypic properties of strain CG-1 T are shown in the species description. The features differentiating strain CG-1 T from closely related species are presented in Table 1.Polar lipids were extracted with chloroform/methanol as previously described (Corcelli et al, 2000). TLC was carried out using Merck TLC silica gel 60 plates (Art.…”