title: Evolution of vitamin B2 biosynthesis: structural and functional similarity between pyrimidine deaminases of eubacterial and plant origin.
abstract: The Arabidopsis thaliana open reading frame At4g20960 predicts a protein whose N-terminal part is similar to the eubacterial 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate deaminase domain. A synthetic open reading frame specifying a pseudomature form of the plant enzyme directed the synthesis of a recombinant protein which was purified to apparent homogeneity and was shown by NMR spectroscopy to convert 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate into 5-amino-6-ribosylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate at a rate of 0.9 micromol mg(-1) min(-1). The substrate and product of the enzyme are both subject to spontaneous anomerization of the ribosyl side chain as shown by (13)C NMR spectroscopy. The protein contains 1 eq of Zn(2+)/subunit. The deaminase activity could be assigned to the N-terminal section of the plant protein. The deaminase domains of plants and eubacteria share a high degree of similarity, in contrast to deaminases from fungi. These data show that the riboflavin biosynthesis in plants proceeds by the same reaction steps as in eubacteria, whereas fungi use a different pathway.
authors.affiliation: Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, Garching D-85747, Germany. markus.fischer@ch.tum.de
authors.forename: Markus
authors.initials: M
authors.lastname: Fischer
authors.forename: Werner
authors.initials: W
authors.lastname: Römisch
authors.forename: Sabine
authors.initials: S
authors.lastname: Saller
authors.forename: Boris
authors.initials: B
authors.lastname: Illarionov
authors.forename: Gerald
authors.initials: G
authors.lastname: Richter
authors.forename: Felix
authors.initials: F
authors.lastname: Rohdich
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.forename: Adelbert
authors.initials: A
authors.lastname: Bacher
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D001412:Bacillus subtilis / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry; D001483:Base Sequence; D001669:Biochemical Phenomena; D001671:Biochemistry; D002352:Carrier Proteins / Q000737:chemistry; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism; D004262:DNA Restriction Enzymes / Q000494:pharmacology; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D019143:Evolution, Molecular; D006136:GTP Cyclohydrolase / Q000737:chemistry; D005816:Genetic Complementation Test; D006160:Guanosine Triphosphate / Q000737:chemistry; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D058619:Maltose-Binding Proteins; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D009709:Nucleotide Deaminases / Q000737:chemistry* / Q000378:metabolism*; D009841:Oligonucleotides / Q000737:chemistry; D016366:Open Reading Frames; D010802:Phylogeny; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D012256:Riboflavin / Q000096:biosynthesis*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization; D013054:Spectrophotometry, Atomic; D013401:Sugar Alcohol Dehydrogenases / Q000737:chemistry; D013997:Time Factors; D015032:Zinc / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D018076:DNA, Complementary; D058619:Maltose-Binding Proteins; D009841:Oligonucleotides; D011994:Recombinant Proteins; D006160:Guanosine Triphosphate; D004247:DNA; D013401:Sugar Alcohol Dehydrogenases; D004262:DNA Restriction Enzymes; C104886:RibG protein, Bacillus subtilis; D009709:Nucleotide Deaminases; D006136:GTP Cyclohydrolase; D015032:Zinc; D012256:Riboflavin