Biosynthesis of Caffeine Underlying the Diversity of Motif B’ Methyltransferase

Abstract

Theobroma spp. The caffeine biosynthetic pathway depends on the substrate specificity of N-methyltransferases, which are members of the motif Bʹ methyltransferase family. The caffeine biosynthetic pathways in purine alkaloid-containing plants might have evolved in parallel with one another, consistent with different catalytic properties of the enzymes involved in these pathways.

Biosynthetic Pathways of Purine and Pyridine Alkaloids in Coffee Plants

“…In caffeine and trigonelline biosynthesis, the key reactions are methylation of the purine and pyridine skeletons. The methyl groups are donated from S-adenosyl-Lmethionine (SAM) by a special group of N-methyltransferases called the "motif B′-methyltransferase" or the "SABATH familymethyltransferase" [8].…”

miR828a-CsMYB114 Module Negatively Regulates the Biosynthesis of Theobromine in Camellia sinensis

“…In tea plants, the predominant biochemical pathway for the synthesis of caffeine follows these sequential steps: starting from xanthosine, it transforms into 7-methylxanthosine, then proceeds to become 7-methylxanthine, followed by conversion to theobromine, and finally culminates in the formation of caffeine . In the pathway, S -adenosyl- l -methionine (SAM) functions as a methyl donor, facilitating the methylation of purine bases at specific stages of the process . In most plants, the conserved structural domains A, B′, and C serve as binding sites for the methyl donor SAMa .…”