Adenosylhopane: The first intermediate in hopanoid side chain biosynthesis

Bradley, Alexander S.; Pearson, Ann; Sáenz, James; Marx, Christopher J.

doi:10.1016/j.orggeochem.2010.07.003

Cited by 82 publications

(110 citation statements)

References 39 publications

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“…S1), which together make up most of the total hopanoid content (27). M. extorquens also produces extended side-chain polar hopanoids, known as bacteriohopanepolyols (BHPs), predominately composed of a bacteriohopanetetrol cyclitol ether (BHT-CE) and its guanidine-modified derivative (BHT-GCE) (28) (Fig.…”

Section: Resultsmentioning

confidence: 99%

Hopanoids as functional analogues of cholesterol in bacterial membranes

Sáenz

Grosser

Bradley

et al. 2015

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

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198

174

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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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Section: Resultsmentioning

confidence: 99%

Hopanoids as functional analogues of cholesterol in bacterial membranes

Sáenz

Grosser

Bradley

et al. 2015

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

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198

174

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“…Kim et al (2011) found that the lowest relative abundance of adenosylhopane (the dominant soil marker BHP) occurred at low altitude where MAAT was high, pH more alkaline and precipitation lowest. This could suggest that, during BHP synthesis, adenosylhopane (an intermediate in hopanoid biosynthesis; Bradley et al, 2010) is converted to other BHPs when environmental conditions are favourable for microbial activity (e.g. warmer).…”

Section: Trends In Global Bhp Distributionmentioning

confidence: 99%

“…The initial step in BHP synthesis is the cyclisation of squalene (controlled via the sqhC gene), with the addition of the hopanoid side chain (via the hpnH gene), leading to the production of 30-(5 0 -adenosyl)hopane (adenosylhopane; 1a; Fig. 1; Bradley et al, 2010). It is believed that all hopanoid producing bacteria synthesise adenosylhopane as a BHP precursor; however, few hopanoid producers have been observed accumulating adenosylhopane and only one species has been found to contain the related compound, adenosylhopane type 2 (1c) (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…All species in which adenosylhopane has been identified were also found to contain a range of other BHPs, including bacterioho 33,34,33, or both van Winden et al, 2012b). These and other BHPs are formed following cleavage of the adenine moiety (Bradley et al, 2010;Liu et al, 2014), but it is unknown why accumulation of adenosylhopane occurs only in terrestrial systems (soils in particular) and not in marine sediments. This suggests that the function of adenosylhopane is not restricted to that of a biosynthetic precursor, or it would likely accumulate in all settings.…”

Section: Introductionmentioning

confidence: 99%

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Bacteriohopanepolyols in tropical soils and sediments from the Congo River catchment area

Spencer-Jones

Wagner

Dinga³

et al. 2015

Organic Geochemistry

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a b s t r a c tThe Congo River basin drains the second largest area of tropical rainforest in the world, including a large proportion of pristine wetlands. We present the bacteriohopanepolyol (BHP) inventory of a suite of tropical soils and, from comparison with published data, propose some initial ideas on BHP distribution controls. Strong taxonomic controls on BHP production are evident in wetland sediments. Dominant within the suite were 35-aminobacteriohopane-31,32,33,34-tetrol (aminotetrol) and 35-aminobacterio hopane-30,31,32,33,34-pentol (aminopentol), indicating aerobic methanotrophy. A narrow range and low mean relative abundance of 30-(5 0 -adenosyl)hopane (adenosylhopane) and related compounds, collectively termed ''soil marker" BHPs, were observed in Congo soils (mean 17%, range 7.9-36% of total BHPs, n = 22) compared with literature data from temperate surface soils and Arctic surface soils (mean 36%, range 0-66% of total BHPs, n = 28) suggesting a greater rate of conversion of these BHP precursors to other structures.

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“…In modern sediments, functionalized BHPs are being explored as diagnostic for varying clades of bacteria (reviewed by ).In rocks and oils,the relative abundance of different hopane isomers can provide information about both environmental conditions during deposition, as well as maturity (Seifert and Moldowan, 1980;Brassell et al, 1983;Peters and Moldowan, 1991;Peters et al, 2005). For ancient rocks, hopanoids methylated at C-2 or C-3 have received particular attention because they have been proposed as diagnostic markers for cyanobacteria and aerobic methylotrophs, respectively (Zundel and Rohmer, 1985a,b;Summons and Jahnke, 1990;Summons et al, 1994Summons et al, , 1999Farrimond et al, 2004).A current research focus lies in understanding the cellular function of BHPs in bacteria, the genetic basis for their biosynthesis and modification, and their distribution and evolutionary relationships among extant organisms (Fischer et al, 2005;Blumenberg et al, 2006;Fischer and Pearson, 2007;Rashby et al, 2007;Doughty et al, 2009;Welander et al, 2009Welander et al, , 2010Welander et al, , 2012Bradley et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Identification and quantification of polyfunctionalized hopanoids by high temperature gas chromatography–mass spectrometry

Sessions

Zhang

Welander

et al. 2013

Organic Geochemistry

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Hopanoids are triterpenoids produced mainly by bacteria, are ubiquitous in the environment, and have many important applications as biological markers. A wide variety of related hopanoid structures exists, many of which are polyfunctionalized. These modifications render the hopanoids too involatile for conventional gas chromatography (GC) separation, so require either laborious oxidative cleavage of the functional groups or specialized high temperature (HT) columns. Here we describe the systematic evaluation and optimization of a HT-GC method for the analysis of polyfunctionalized hopanoids and their methylated homologs. Total lipid extracts are derivatized with acetic anhydride and no further treatment or workup is required. We show that acid or base hydrolysis to remove di-and triacylglycerides leads to degradation of several BHP structures. DB-XLB type columns can elute hopanoids up to bacteriohopane-tetrol at 350 °C, with baseline separation of all 2-methyl/desmethyl homologs. DB-5HT type columns can additionally elute bacteriohopaneaminotriol and bacteriohopaneaminotetrol, but do not fully separate 2-methyl/ desmethyl homologs. The method gave 2-to 7-fold higher recovery of hopanoids than oxidative cleavage and can provide accurate quantification of all analytes including 2-methyl hopanoids. By comparing data from mass spectra with those from a flame ionization detector, we show that the mass spectromet (MS) response factors for different hopanoids using either total ion counts or m/z 191 vary substantially. Similarly, 2-methyl ratios estimated from selected-ion data are lower than those from FID by 10-30% for most hopanoids, but higher by ca. 10% for bacteriohopanetetrol. Mass spectra for a broad suite of hopanoids, including 2-methyl homologs, from Rhodopseudomonas palustris are presented, together with the tentative assignment of several new hopanoid degradation products.

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Adenosylhopane: The first intermediate in hopanoid side chain biosynthesis

Cited by 82 publications

References 39 publications

Hopanoids as functional analogues of cholesterol in bacterial membranes

Hopanoids as functional analogues of cholesterol in bacterial membranes

Bacteriohopanepolyols in tropical soils and sediments from the Congo River catchment area

Identification and quantification of polyfunctionalized hopanoids by high temperature gas chromatography–mass spectrometry

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