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Showing 1-25 of 25 results for "04626" within Papers
H Schulenberg-Schell et al.
Analytical biochemistry, 181(1), 120-124 (1989-08-15)
A rapid and sensitive method for determination of various hopanoids in microorganisms is described. Tetrahydroxybacteriohopane (THBH), THBH-ether and -glycoside were acetylated with acetanhydride/pyridine and were separated on a C18 reversed-phase HPLC column with a gradient of acetonitrile in methanol and
K Poralla et al.
FEMS microbiology letters, 189(1), 93-95 (2000-07-29)
Streptomyces coelicolor A3(2) contains a cluster of putative isoprenoid and hopanoid biosynthetic genes. The strain does not produce the pentacyclic hopanoids in liquid culture but produces them on solid medium when sporulating. Mutants defective in the formation of aerial mycelium
Tsutomu Sato et al.
Bioscience, biotechnology, and biochemistry, 68(3), 728-738 (2004-04-02)
To provide insight into the catalytic mechanism for the final deprotonation reaction of squalene-hopene cyclase (SHC) from Alicyclobacillus acidocaldarius, mutagenesis experiments were conducted for the following ten residues: Thr41, Glu45, Glu93, Arg127, Trp133, Gln262, Pro263, Tyr267, Phe434 and Phe437. An
B Andes Hess et al.
Organic letters, 6(11), 1717-1720 (2004-05-21)
The cyclization of the A-B rings of squalene to hopene is studied computationally (DFT). A transition structure is found for a concerted, asynchronous pathway for the formation of chair-chair decalin carbocation. The computationally derived conformer leading to this asynchronous transition
Tsutomu Hoshino et al.
Organic letters, 4(15), 2553-2556 (2002-07-19)
[reaction: see text] Incubation of (6E,10E,14E,18E)-2,6,10,19,23-pentamethyl-tetracosa-2,6,10,14,18,22-hexaene with Alicyclobacillus acidocaldarius hopene cyclase afforded four products having two types of carbocyclic skeletons, i.e., two hopane products and two products having an unprecedented carbocyclic skeleton of 6/5 + 5/5 +6 pentacyclic and 6/5
M Vyssotski et al.
Lipids, 46(12), 1155-1161 (2011-08-02)
A Gram-negative, aerobic, pink-pigmented, rod-shaped bacterium Chthonomonas calidirosea (strain T49(T)) with an optimal temperature for growth of 68 °C, isolated from soil samples from Hell's Gate in the Tikitere geothermal system (New Zealand), was the first cultivated bacterium of the novel
Dirk J Reinert et al.
Chemistry & biology, 11(1), 121-126 (2004-04-29)
The membrane protein squalene-hopene cyclase was cocrystallized with 2-azasqualene and analyzed by X-ray diffraction to 2.13 A resolution. The conformation of this close analog was clearly established, and it agreed with the common textbook presentation. The bound squalene undergoes only
M Rohmer et al.
European journal of biochemistry, 112(3), 541-547 (1980-12-01)
1. A cell-free system from the bacterium Acetobacter pasteurianum was incubated with [12-3H]squalene; diploptene and diplopterol, hopanoids normally present in the bacterium, were labelled. Their radioactivity was confirmed by purification using thin-layer chromatography, synthesis of derivatives and recrystallization to constant
Seiichi P T Matsuda et al.
Organic & biomolecular chemistry, 4(3), 530-543 (2006-02-01)
Most quantum mechanical studies of triterpene synthesis have been done on small models. We calculated mPW1PW91/6-311+G(2d,p)//B3LYP/6-31G* energies for many C30H51O+ intermediates to establish the first comprehensive energy profiles for the cationic cyclization of oxidosqualene to lanosterol, lupeol, and hopen-3beta-ol. Differences
M Perzl et al.
Microbiology (Reading, England), 143 ( Pt 4), 1235-1242 (1997-04-01)
With the help of a PCR-based screening method, the gene encoding squalenehopene cyclase (SHC) of Bradyrhizobium japonicum USDA 110 was isolated from a cosmid library. The SHC catalyses the cyclization of squalene to hopanoids, a class of triterpenoid lipids recently
F G Prahl et al.
Limnology and oceanography, 37(6), 1290-1300 (1992-01-01)
The pentacyclic triterpene 17 beta(H),21 beta(H)-hop-22(29)-ene (diploptene) occurs in sediments throughout the Columbia River drainage basin and off the southern coast of Washington state in concentrations comparable to long-chain plantwax n-alkanes. The same relationship is evident for diploptene and long-chain
Lidia Smentek et al.
Journal of the American Chemical Society, 132(48), 17111-17117 (2010-11-18)
The long-standing question of what is the nature of the cyclization of squalene to form tetracyclic and pentacyclic triterpenes has been addressed computationally. Using the DFT method with an intrinsic reaction coordinate calculation, we find that the first three rings
Tsutomu Hoshino et al.
Organic & biomolecular chemistry, 2(10), 1456-1470 (2004-05-12)
To provide insight into the polycyclization mechanism of squalene by squalene-hopene cyclase (SHC) from Alicyclobacilus acidocaldarius, some analogs of nor- and bisnorsqualenes were synthesized including the deuterium-labeled squalenes and incubated with the wild-type SHC, leading to the following inferences. (1)
T Sato et al.
Bioscience, biotechnology, and biochemistry, 62(2), 407-411 (1998-04-09)
An overexpression system for squalene-hopene cyclase (SHC) was constructed by using the pET3a vector, which is responsible for high expression with help from the strong T7 promoter when incorporated into E. coli BL21(DE3). Site-directed mutagenesis experiments prove that two amino
Marcin Nowosielski et al.
Journal of molecular modeling, 17(9), 2169-2174 (2011-05-13)
The analysis of biochemical processes is one of the main challenges for modern computational chemistry. Probably the biggest issue facing scientists in this case is the number of factors that have to be taken into account, as even those factors
Gopal Prasad Ghimire et al.
Biotechnology letters, 31(4), 565-569 (2009-01-01)
Squalene-hopene cyclase, which catalyzes the complex cyclization of squalene to the pentacyclic triterpene, hopene, is a key enzyme in the biosynthesis of hopanoids. The deduced amino acid sequence of the Streptomyces peucetius gene (spterp25) had significant similarity to other prokaryotic
T Hoshino et al.
Bioscience, biotechnology, and biochemistry, 63(11), 2038-2041 (2000-01-15)
Three triterpenes having the 6/6/5-fused tri- and 6/6/6/5-fused tetracyclic skeletons were isolated from an incubation mixture of the mutated F601A enzyme, these products being in accordance with a Markovnikov closure. Successful trapping of the tricyclic cationic intermediate by using the
Martin Blumenberg et al.
FEMS microbiology letters, 293(1), 73-78 (2009-02-19)
Hopanoids are important lipid components of many bacterial groups and are therefore ubiquitous in soils, sediments, and rocks. Until recently, it was believed that the synthesis of hopanoids is restricted to at least microaerophilic bacteria and consequently geological findings of
Karl Poralla
Chemistry & biology, 11(1), 12-14 (2004-04-29)
In this issue of Chemistry & Biology, our understanding of the formation of pentacyclic hopene from the linear squalene is enhanced by an X-ray structure of a complex between squalene-hopene cyclase and the substrate analog 2-azasqualene.
Masahiko Isaka et al.
Journal of natural products, 73(4), 688-692 (2010-04-07)
Two new triterpenes, 17(21)-hopene-6alpha,12beta-diol (1) and 17(21)-hopen-12beta-ol (2), the known 17(21)-hopen-6alpha-ol (zeorinin, 3), and two new biarylic dihydronaphthopyrones, aschernaphthopyrones A (4) and B (5), were isolated from the scale insect pathogenic fungus Aschersonia paraphysata BCC 11964. Hopene 1 and aschernaphthopyrone
Thomas Härtner et al.
FEMS microbiology letters, 243(1), 59-64 (2005-01-26)
Geobacter metallireducens and G. sulfurreducens have been classified as strictly anaerobic bacteria which grow and thrive in subsurface and sediment environments. Hopanoids are pentacyclic triterpenoid lipids and are important for bacterial membrane stability and functioning. Hopanoids predominantly occur in aerobically
Gabriele Siedenburg et al.
Applied and environmental microbiology, 77(12), 3905-3915 (2011-05-03)
Hopanoids and sterols are members of a large group of cyclic triterpenoic compounds that have important functions in many prokaryotic and eukaryotic organisms. They are biochemically synthesized from linear precursors (squalene, 2,3-oxidosqualene) in only one enzymatic step that is catalyzed
Ryan F Seipke et al.
Journal of bacteriology, 191(16), 5216-5223 (2009-06-09)
Hopanoids are triterpenoic, pentacyclic compounds that are structurally similar to sterols, which are required for normal cell function in eukaryotes. Hopanoids are thought to be an important component of bacterial cell membranes because they control membrane fluidity and diminish passive
Ramkumar Rajamani et al.
Journal of the American Chemical Society, 125(42), 12768-12781 (2003-10-16)
Molecular dynamics simulations with a combined quantum mechanical and molecular mechanical (QM/MM) potential have been carried out to investigate the squalene-to-hopene carbocation cyclization mechanism in squalene-hopene cyclase (SHC). The present study is based on free energy simulations by constructing the
E Douka et al.
FEMS microbiology letters, 199(2), 247-251 (2001-05-30)
Twelve polycyclic triterpenic hydrocarbons (alpha- and gamma-polypodatetraenes, dammara-20(21),24-diene, 17-isodammara-12,24-diene, eupha-7,24-diene, hop-17(21)-ene, neohop-13(18)-ene, 17-isodammara-20(21),24-diene, neohop-12-ene, fern-8-ene, diploptene and hop-21-ene) were detected in the hydrocarbon fraction from the bacterium Zymomonas mobilis. Some of them have never been reported from bacteria. These triterpenes
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