Biosynthesis of riboflavin in archaea studies on the mechanism of 3,4-dihydroxy-2-butanone-4-phosphate synthase of Methanococcus jannaschii.
The hypothetical protein predicted by the open reading frame MJ0055 of Methanococcus jannaschii was expressed in a recombinant Escherichia coli strain under the control of a synthetic gene optimized for translation in an eubacterial host. The recombinant protein catalyzes the formation of the riboflavin precursor 3,4-dihydroxy-2-butanone 4-phosphate from ribulose 5-phosphate at a rate of 174 nmol mg(-1) min(-1) at 37 degrees C. The homodimeric 51.6-kDa protein requires divalent metal ions, preferentially magnesium, for activity. The reaction involves an intramolecular skeletal rearrangement as shown by (13)C NMR spectroscopy using [U-(13)C(5)]ribulose 5-phosphate as substrate. A cluster of charged amino acid residues comprising arginine 25, glutamates 26 and 28, and aspartates 21 and 30 is essential for catalytic activity. Histidine 164 and glutamate 185 were also shown to be essential for catalytic activity.
Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, D-85747 Garching, Germany. markus.fischer@ch.tum.de
Markus
M
Fischer
Werner
W
Romisch
Susanne
S
Schiffmann
Mark
M
Kelly
Hartmut
H
Oschkinat
Stefan
S
Steinbacher
Robert
R
Huber
Wolfgang
W
Eisenreich
Gerald
G
Richter
Adelbert
A
Bacher
D000595:Amino Acid Sequence; D001483:Base Sequence; D009682:Magnetic Resonance Spectroscopy; D017017:Methanococcus / Q000378:metabolism*; D008969:Molecular Sequence Data; D012256:Riboflavin / Q000096:biosynthesis*; D013403:Sugar Phosphates / Q000378:metabolism*
D013403:Sugar Phosphates; C066494:3,4-dihydroxy-2-butanone-4-phosphate; D012256:Riboflavin