title: Biosynthesis of tetrahydrofolate. Stereochemistry of dihydroneopterin aldolase.
abstract: 7,8-Dihydroneopterin aldolase catalyzes the formation of the tetrahydrofolate precursor, 6-hydroxymethyl-7,8-dihydropterin, and is a potential target for antimicrobial and anti-parasite chemotherapy. The last step of the enzyme-catalyzed reaction is believed to involve the protonation of an enol type intermediate. In order to study the stereochemical course of that reaction step, [1',2',3',6,7-13C5]dihydroneopterin was treated with aldolase in deuterated buffer. The resulting, partially deuterated [6alpha,6,7-13C3]6-hydroxymethyl-7,8-dihydropterin was converted to partially deuterated 6-(R)-[6,7,9,11-13C4]5,10-methylenetetrahydropteroate by a sequence of three enzyme-catalyzed reactions followed by treatment with [13C]formaldehyde. The product was analyzed by multinuclear NMR spectroscopy. The data show that the carbinol group of enzymatically formed 6-hydroxymethyl-dihydropterin contained 2H predominantly in the pro-S position.
authors.affiliation: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany.
authors.forename: Victoria
authors.initials: V
authors.lastname: Illarionova
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.forename: Christoph
authors.initials: C
authors.lastname: Haussmann
authors.forename: Werner
authors.initials: W
authors.lastname: Romisch
authors.forename: Gerald
authors.initials: G
authors.lastname: Richter
authors.forename: Adelbert
authors.initials: A
authors.lastname: Bacher
mesh_terms: D000446:Aldehyde-Lyases / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004094:Dihydropteroate Synthase / Q000737:chemistry / Q000302:isolation & purification; D017854:Diphosphotransferases / Q000737:chemistry / Q000302:isolation & purification; D005634:Fructose-Bisphosphate Aldolase / Q000494:pharmacology; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D010957:Plasmids / Q000378:metabolism; D011622:Pterins / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification; D013237:Stereoisomerism; D013763:Tetrahydrofolates / Q000096:biosynthesis* / Q000737:chemistry*
chemical_list: D011622:Pterins; D011994:Recombinant Proteins; D013763:Tetrahydrofolates; C000978:dihydropteroate; C030371:5,6,7,8-tetrahydrofolic acid; D004094:Dihydropteroate Synthase; D017854:Diphosphotransferases; C019684:2-amino-4-hydroxy-6-hydroxymethyldihydropteridine pyrophosphokinase; D000446:Aldehyde-Lyases; D005634:Fructose-Bisphosphate Aldolase; C020044:dihydroneopterin aldolase