A glycolipid containing hopane isolated from the acidophilic, thermophilic <i>bacillus acidocaldarius</i>, has a cholesterol‐like function in membranes

Poralla, Karl; Kannenberg, Elmar L.; Blume, Alfred

doi:10.1016/0014-5793(80)80506-0

Cited by 112 publications

(56 citation statements)

References 13 publications

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“…This interaction provides the mechanistic basis for the underlying interconnectivity supporting membrane lateral segregation and promoting a fluid but mechanically robust plasma membrane (12). Early investigations showed that both sterols and hopanoids exhibit the ability to condense lipids (13,14). We demonstrated that hopanoids are indeed bacterial sterol surrogates with respect to their ability to form a liquid ordered phase, and that they promote liquid-liquid phase separation in membranes (15).…”

mentioning

confidence: 77%

Hopanoids as functional analogues of cholesterol in bacterial membranes

Sáenz

Grosser

Bradley

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

213

177

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The functionality of cellular membranes relies on the molecular order imparted by lipids. In eukaryotes, sterols such as cholesterol modulate membrane order, yet they are not typically found in prokaryotes. The structurally similar bacterial hopanoids exhibit similar ordering properties as sterols in vitro, but their exact physiological role in living bacteria is relatively uncharted. We present evidence that hopanoids interact with glycolipids in bacterial outer membranes to form a highly ordered bilayer in a manner analogous to the interaction of sterols with sphingolipids in eukaryotic plasma membranes. Furthermore, multidrug transport is impaired in a hopanoid-deficient mutant of the gram-negative Methylobacterium extorquens, which introduces a link between membrane order and an energy-dependent, membrane-associated function in prokaryotes. Thus, we reveal a convergence in the architecture of bacterial and eukaryotic membranes and implicate the biosynthetic pathways of hopanoids and other order-modulating lipids as potential targets to fight pathogenic multidrug resistance.

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mentioning

confidence: 77%

Hopanoids as functional analogues of cholesterol in bacterial membranes

Sáenz

Grosser

Bradley

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

213

177

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“…They have a structure similar to that of sterols (18) and condense phospholipids in mnodel membrane systems (2,22) and supposedly in cellular membranes. Hopanoids are more effectively produced at higher growth temperatures by Bacillus acidocaldarius (21), Zymomonas mobilis (26), and Rhodospirillum acidophila (12) and at high ethanol levels by Z. mobilis (6).…”

mentioning

confidence: 93%

Cloning, expression, and sequencing of squalene-hopene cyclase, a key enzyme in triterpenoid metabolism

et al. 1992

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The pentacyclic hopanoids, a class of eubacterial lipids, are synthesized by squalene-hopene cyclase and side chain-elongating enzymes. With the aid of DNA probes based on the amino-terminal sequence of purified squalene-hopene cyclase from Bacillus acidocaldarius, clones of Escherichia coi that express this enzy'me in the cytoplasmic membrane were isolated. According to the DNA sequence, the cyclase contained 627 amino acids with a molecular mass of 69,473 Da. A high percentage of the amino acids were basic. No significant similarity to existing sequenced proteins was found.Hopanoids are a class of pentacyclic triterpenoids that occur in all crude oils (18) and are also widespread eubacterial lipids (19,24). They have a structure similar to that of sterols (18) and condense phospholipids in mnodel membrane systems (2, 22) and supposedly in cellular membranes. Hopanoids are more effectively produced at higher growth temperatures by Bacillus acidocaldarius (21), Zymomonas mobilis (26), and Rhodospirillum acidophila (12) and at high ethanol levels by Z. mobilis (6). In Mycoplasma mycoides they are able to replace sterols (11). It was recently found that the N2-fixing symbiont Frankia sp. contains high levels of hopanoids (3).In contrast to sterol biosynthesis, the biosynthesis of hopanoids is independent of molecular oxygen as a substrate. Hopanoids are cyclized directly from squalene by squalene-hopene cyclase (28), which may be homologous to sterol cyclases and other triterpenoid cyclases from eucaryotic cells, synthesizing by a similar reaction a similar product with analogous membrane properties. It would therefore be of interest to compare the amino acid sequence of hopene cyclase with those of sterol cyclases, thereby increasing our understanding of the recruitment of these enzymes. If homologies are found, in vitro mutagenesis studies would be of value in understanding the evolution of sterol cyclases. So far no triterpenoid cyclase has been sequenced. As a first step in this direction, the squalene-hopene cyclase gene from B. acidocaldarius was cloned, expressed, and sequenced; this enzyme appears to represent a new gene family. MATERIALS AND METHODSBacterial strains and plasmids. The source of squalenehopene cyclase and genomic DNA was B. acidocaldarius ATCC 27009. Escherichia coli BMH71-18 (14) was used for transformation. Plasmid pUC19 was described previously (31).Culture conditions. B. acidocaldarius was grown on sporulation medium at pH 3 and 60°C (8). E. coli was grown at 37°C in LB medium (GIBCO, Neuisenburg, Germany) or on LB plates, both containing 30 mg of ampicillin per liter, when plasmid-containing cells were selected. * Corresponding author. DNA preparation. B. acidocaldarius grown to the early exponential phase was harvested by centrifugation and washed with 150 mM NaCl-10 mM EDTA (pH 8.0) (SE). The wet cells (1 g) were resuspended in 10 ml of SE. After lysozyme (1 mg/ml) was added, the suspension was incubated at 37°C. After 1 h, the cells were lysed by the addition of 200 ,ul of 20% (wt/v...

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“…Strains of the genus Alicyclobacillus have been isolated from solfataric soils within geothermal areas and several nongeothermal soils (Darland & Brock, 1971 ;Deinhard et al, 1987a, b). Most of the interest in these organisms revolves around the study of the role of ω-cyclic fatty acids and hopanoids on membrane function (Poralla et al, 1980 ;Kannenberg et al, 1984), but there is also considerable interest in the biotechnological application of thermostable enzymes derived from A. acidocaldarius-like strains (Schwermann et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Alicyclobacillus hesperidum sp. nov. and a related genomic species from solfataric soils of São Miguel in the Azores.

Albuquerque¹,

Rainey²,

Chung³

et al. 2000

International Journal of Systematic and Evolutionary Microbiology

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Several acidophilic, slightly thermophilic or thermophilic Gram-positive isolates were recovered from solfataric soil at Furnas on the Island of Sa 4 o Miguel in the Azores. Phylogenetic analysis of the 16S rRNA gene sequence showed that these organisms represented two novel species of the genus Alicyclobacillus. Strains FR-11 T and FR-1b had an optimum growth temperature of about 50 SC, whereas strains FR-3 and FR-6 T had an optimum growth temperature of about 60 SC. Biochemical, physiological and chemotaxonomic characteristics did not distinguish isolates FR-3 and FR-6T from the type strain of Alicyclobacillus acidocaldarius ; however, strains FR-11 T and FR-1b could be easily distinguished from the type strain of Alicyclobacillus acidoterrestris by the carbon source assimilation pattern and the fatty acid composition. On the basis of the phylogenetic analysis, physiological and biochemical characteristics, and fatty acid composition the name Alicyclobacillus hesperidum is proposed for the species represented by strains FR-11 T and FR-1b ; a formal name for the new genomic species represented by strains FR-3 and FR-6 T is not proposed at this time.

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A glycolipid containing hopane isolated from the acidophilic, thermophilic bacillus acidocaldarius, has a cholesterol‐like function in membranes

Cited by 112 publications

References 13 publications

Hopanoids as functional analogues of cholesterol in bacterial membranes

Hopanoids as functional analogues of cholesterol in bacterial membranes

Cloning, expression, and sequencing of squalene-hopene cyclase, a key enzyme in triterpenoid metabolism

Alicyclobacillus hesperidum sp. nov. and a related genomic species from solfataric soils of São Miguel in the Azores.

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