The Tzs protein from Agrobacterium tumefaciens C58 produces zeatin riboside 5'-phosphate from 4-hydroxy-3-methyl-2-(E)-butenyl diphosphate and AMP.
The plant pathogen Agrobacterium tumefaciens produces cytokinins upon induction of the virulence genes by secondary metabolites from wounded plants, and these hormones are believed to stimulate the infection process. To study the biosynthetic pathway, the tzs gene, encoding the Tzs (trans-zeatin-synthesizing) protein from A. tumefaciens, was cloned and the protein was overproduced and purified. Analysis of its reactivity with radioactively labeled substrate demonstrated conversion of 4-hydroxy-3-methyl-2-(E)-butenyl diphosphate, a product of the deoxyxylulose phosphate pathway, with AMP to zeatin riboside 5'-phosphate. This suggests that A. tumefaciens uses an alternative pathway of cytokinin biosynthesis, which had previously been hypothesized to operate in plants.
Krall
Lilian
L
Department Biologie I, Ludwig-Maximilians-Universität, Bereich Mikrobiologie, Maria-Ward-Str. 1a, D-80638, München, Germany.
Raschke
Maja
M
Zenk
Meinhart H
MH
Baron
Christian
C
D000249:Adenosine Monophosphate / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D007541:Isopentenyladenosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism*; D010755:Organophosphates / Q000737:chemistry / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods
C467061:4-hydroxy-3-methyl-2-butenyl diphosphate; D001426:Bacterial Proteins; D010755:Organophosphates; C467060:zeatin riboside 5'-phosphate; D000249:Adenosine Monophosphate; D007541:Isopentenyladenosine