Evolution of putrescine N-methyltransferase from spermidine synthase demanded alterations in substrate binding.
Putrescine N-methyltransferase (PMT) catalyses S-adenosylmethionine (SAM)-dependent methylation of putrescine in tropane alkaloid biosynthesis. PMT presumably evolved from the ubiquitous spermidine synthase (SPDS). SPDS protein structure suggested that only few amino acid exchanges in the active site were necessary to achieve PMT activity. Protein modelling, mutagenesis, and chimeric protein construction were applied to trace back evolution of PMT activity from SPDS. Ten amino acid exchanges in Datura stramonium SPDS dismissed the hypothesis of facile generation of PMT activity in existing SPDS proteins. Chimeric PMT and SPDS enzymes were active and indicated the necessity for a different putrescine binding site when PMT developed.
Institute of Pharmacy, Faculty of Science I, Martin Luther University Halle-Wittenberg, Hoher Weg 8, D-06120 Halle, Germany.
Stefan
S
Biastoff
Nicole
N
Reinhardt
Veaceslav
V
Reva
Wolfgang
W
Brandt
Birgit
B
Dräger
D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D013286:Datura stramonium / Q000201:enzymology / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D008780:Methyltransferases / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D011700:Putrescine / Q000737:chemistry / Q000378:metabolism*; D012436:S-Adenosylmethionine / Q000378:metabolism; D016415:Sequence Alignment; D011436:Spermidine Synthase / Q000737:chemistry / Q000145:classification / Q000235:genetics / Q000378:metabolism*
D012436:S-Adenosylmethionine; D008780:Methyltransferases; C112598:putrescine N-methyltransferase; D011436:Spermidine Synthase; D011700:Putrescine