In vitro biosynthesis and in vivo processing of the major microneme antigen ofSarcocystis muris cyst merozoites

1996 ◽  
Vol 82 (5) ◽  
pp. 468-474 ◽  
Author(s):  
H. Klein ◽  
H. Mehlhorn ◽  
W. Rüger
2007 ◽  
Vol 79 (12) ◽  
pp. 2179-2188 ◽  
Author(s):  
A. Ian Scott ◽  
Charles A. Roessner

The genetic engineering of Escherichia coli for the over-expression of enzymes of the aerobic and anaerobic pathways to cobalamin has resulted in the in vivo and in vitro biosynthesis of new intermediates and other products that were isolated and characterized using a combination of bioorganic chemistry and high-resolution NMR. Analyses of these products were used to deduct the functions of the enzymes that catalyze their synthesis. CobZ, another enzyme for the synthesis of precorrin-3B of the aerobic pathway, has recently been described, as has been BluB, the enzyme responsible for the oxygen-dependent biosynthesis of dimethylbenzimidazole. In the anaerobic pathway, functions have recently been experimentally confirmed for or assigned to the CbiMNOQ cobalt transport complex, CbiA (a,c side chain amidation), CbiD (C-1 methylation), CbiF (C-11 methylation), CbiG (lactone opening, deacylation), CbiP (b,d,e,g side chain amidation), and CbiT (C-15 methylation, C-12 side chain decarboxylation). The dephosphorylation of adenosylcobalamin-phosphate, catalyzed by CobC, has been proposed as the final step in the biosynthesis of adenosylcobalamin.


Lipids ◽  
1974 ◽  
Vol 9 (6) ◽  
pp. 419-428 ◽  
Author(s):  
William F. Naccarato ◽  
John R. Gilbertson ◽  
Rose A. Gelman

1992 ◽  
Vol 127 (2) ◽  
pp. 189-192 ◽  
Author(s):  
Y Touitou ◽  
A Boissonnas ◽  
A Bogdan ◽  
A Auzéby

This is a report of a rare and unusual case of adrenal pathology. A patient presented with clinical and biological signs of primary aldosteronism and computed body tomography scan led to our suspecting the presence of a left adrenocortical carcinoma. The in vitro studies performed on the resected tumour showed very low synthesis of mineralocorticoids and glucocorticoids. The patient could not be re-examined until 15 months later, when he still suffered hypertension; another tomography scan revealed a mass on the right adrenal gland. The studies performed on this second tumour confirmed the diagnosis of Conn's adenoma: active in vitro biosynthesis of 18-hydroxy-corticosterone and aldosterone from exogenous tritiated precursors.


1994 ◽  
Vol 5 (5) ◽  
pp. 331-339 ◽  
Author(s):  
R. Traber ◽  
H. Kobel ◽  
H.-R. Loosli ◽  
H. Senn ◽  
B. Rosenwirth ◽  
...  

From fermentations of Tolypocladium niveum supplemented with D-threonine, a novel natural cyclosporin, [Melle4]cyclosporin, was isolated. Its structural elucidation is based on amino acid analysis and spectroscopic data; the amino acid sequence was deduced from two-dimensional NMR investigations applied to the iso-derivative of [Melle4]cyclosporin which, in contrast to the natural product, is present as one homogenous conformation in solution. We show that one of the four N-methyl-L-leucine units of cyclosporin A, namely that in position 4, is replaced by N-methyl-L-isoleucine. The putative mechanism by which D-threonine induces in vivo biosynthesis of [Melle4]cyclosporin is discussed. In vitro biosynthesis of [Melle4]cyclosporin was achieved using the previously described enzymatic system [Lawen and Traber (1993) J Biol Chem268: 20452–20465], thereby demonstrating the high affinity of cyclosporin synthetase for isoleucine in position 4. In a long series of cyclosporins obtained by in vitro and in vivo biosynthesis, [Melle4]cyclosporin represents the first example that is devoid of immunosuppressive efficacy while retaining strong binding to cyclophilin. It exerts potent in vitro anti-HIV-1 activity.


1995 ◽  
Vol 58 (2) ◽  
pp. 172-176 ◽  
Author(s):  
Russell G. Kerr ◽  
Zhengjian Chen

2005 ◽  
Vol 71 (2) ◽  
pp. 790-796 ◽  
Author(s):  
Stefan Uthoff ◽  
Tim Stöveken ◽  
Nikolaus Weber ◽  
Klaus Vosmann ◽  
Erika Klein ◽  
...  

ABSTRACT The bifunctional wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS/DGAT) from Acinetobacter sp. strain ADP1 (formerly Acinetobacter calcoaceticus ADP1) mediating the biosyntheses of wax esters and triacylglycerols was used for the in vivo and in vitro biosynthesis of thio wax esters and dithio wax esters. For in vitro biosynthesis, 5′His6WS/DGAT comprising an N-terminal His6 tag was purified from the soluble protein fraction of Escherichia coli Rosetta(DE3)pLysS (pET23a::5′His6 atf). By employing SP-Sepharose high-pressure and Ni-nitrilotriacetic acid fast-protein liquid chromatographies, a 19-fold enrichment with a final specific activity of 165.2 nmol mg of protein−1 min−1 was achieved by using 1-hexadecanol and palmitoyl-CoA as substrates. Incubation of purified 5′His6WS/DGAT with 1-hexadecanethiol and palmitoyl-CoA as substrates resulted in the formation of palmitic acid hexadecyl thio ester (10.4% relative specific activity of a 1-hexadecanol control). Utilization of 1,8-octanedithiol and palmitoyl-CoA as substrates led to the formation of 1-S-monopalmitoyloctanedithiol and minor amounts of 1,8-S-dipalmitoyloctanedithiol (59.3% relative specific activity of a 1-hexadecanol control). The latter dithio wax ester was efficiently produced when 1-S-monopalmitoyloctanedithiol and palmitoyl-CoA were used as substrates (13.4% specific activity relative to that of a 1-hexadecanol control). For the in vivo biosynthesis of thio wax esters, the knockout mutant Acinetobacter sp. strain ADP1acr1ΩKm, which is unable to produce fatty alcohols, was used. Cultivation of Acinetobacter sp. strain ADP1acr1ΩKm in the presence of gluconate, 1-hexadecanethiol, and oleic acid in nitrogen-limited mineral salts medium resulted in the accumulation of unusual thio wax esters that accounted for around 1.19% (wt/wt) of the cellular dry weight and consisted mainly of oleic acid hexadecyl thioester as revealed by gas chromatography-mass spectrometry.


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