Search results for "Secologanin Tryptamine Alkaloids"
showing 4 items of 14 documents
Construction and expression of a dual vector for chemo-enzymatic synthesis of plant indole alkaloids inEscherichia coli
2010
A dual vector (pQE-70-STR1-SG) containing coding regions of strictosidine synthase (STR1, EC 4.3.3.2) and strictosidine glucosidase (SG, EC 3.2.1.105) from the Indian medicinal plant Rauvolfia serpentina was constructed. Functional expression of the vector in Escherichia coli cells (M15 strain) was proven by isolation of prepurified enzyme extracts, which show both STR1 and SG activities. Incubation of the enzyme in the presence of tryptamine and secologanin delivered the indole alkaloid cathenamine, demonstrating functional co-expression of both STR1- and SG-cDNAs. Cathenamine reduction by sodium borohydride leading to tetrahydroalstonine revealed the chemo-enzymatic indole alkaloid synthe…
A facile chemoenzymatic approach: one-step syntheses of monoterpenoid indole alkaloids.
2010
Facile chemoenzymatic syntheses of cytotoxic monoterpenoid indole alkaloids with novel skeletons and multiple chiral centers are described. Synthesis of these alkaloids was achieved by a simple one-step reaction using strictosidine and 12-aza-strictosidine as the key intermediates. Strictosidines were prepared by coupling of secologanin with tryptamine and 7-aza-tryptamine, respectively, using the immobilized recombinant Rauvolfia strictosidine synthase. A detailed stereochemical analysis is presented herein. The results provide an opportunity for a chemoenzymatic approach that leads to an increased diversification of complex alkaloids with improved structures and activities.
Vomilenine Reductase — a novel Enzyme catalyzing a crucial Step in the Biosynthesis of the Therapeutically applied Antiarrhythmic Alkaloid Ajmaline
2002
Delineation of the biochemical pathway leading to the antiarrhythmic Rauvolfia alkaloid ajmaline has been an important target in biosynthetic research for many years. The biosynthetic sequence starting with tryptamine and the monoterpene secologanin consists of about 10 different steps. Most of the participating enzymes have been detected and characterized previously, except those catalyzing the reduction of the intermediate vomilenine. A novel NADPH-dependent enzyme that reduces the intermediate has been isolated from Rauvolfia serpentina cell suspension cultures. Vomilenine reductase (M(r )43 kDa, temp opt 30 degrees C, pH opt 5.7-6.2), saturates the indolenine double bond of vomilenine w…
3D-Structure and function of strictosidine synthase--the key enzyme of monoterpenoid indole alkaloid biosynthesis.
2008
Strictosidine synthase (STR; EC 4.3.3.2) plays a key role in the biosynthesis of monoterpenoid indole alkaloids by catalyzing the Pictet-Spengler reaction between tryptamine and secologanin, leading exclusively to 3alpha-(S)-strictosidine. The structure of the native enzyme from the Indian medicinal plant Rauvolfia serpentina represents the first example of a six-bladed four-stranded beta-propeller fold from the plant kingdom. Moreover, the architecture of the enzyme-substrate and enzyme-product complexes reveals deep insight into the active centre and mechanism of the synthase highlighting the importance of Glu309 as the catalytic residue. The present review describes the 3D-structure and …