@article {TapernouxLuthi:2004p8016,
	title = {Cloning, functional expression, and characterization of the raffinose oligosaccharide chain elongation enzyme, galactan:galactan galactosyltransferase, from common bugle leaves},
	journal = {Plant Physiol},
	volume = {134},
	number = {4},
	year = {2004},
	month = {Apr},
	pages = {1377{\textendash}87},
	abstract = {Galactan:galactan galactosyltransferase (GGT) is a unique enzyme of the raffinose family oligosaccharide (RFO) biosynthetic pathway. It catalyzes the chain elongation of RFOs without using galactinol (alpha-galactosyl-myoinositol) by simply transferring a terminal alpha-galactosyl residue from one RFO molecule to another one. Here, we report the cloning and functional expression of a cDNA encoding GGT from leaves of the common bugle (Ajuga reptans), a winter-hardy long-chain RFO-storing Lamiaceae. The cDNA comprises an open reading frame of 1215 bp. Expression in tobacco (Nicotiana plumbaginifolia) protoplasts resulted in a functional recombinant protein, which showed GGT activity like the previously described purified, native GGT enzyme. At the amino acid level, GGT shows high homologies (>60\%) to acid plant alpha-galactosidases of the family 27 of glycosylhydrolases. It is clearly distinct from the family 36 of glycosylhydrolases, which harbor galactinol-dependent raffinose and stachyose synthases as well as alkaline alpha-galactosidases. Physiological studies on the role of GGT confirmed that GGT plays a key role in RFO chain elongation and carbon storage. When excised leaves were exposed to chilling temperatures, levels of GGT transcripts, enzyme activities, and long-chain RFO concentrations increased concomitantly. On a whole-plant level, chilling temperatures induced GGT expression mainly in the roots and fully developed leaves, both known RFO storage organs of the common bugle, indicating an adaptation of the metabolism from active growth to transient storage in the cold.},
	keywords = {Ajuga, Amino Acid Sequence, Cloning: Molecular, Cold Temperature, DNA: Complementary, Galactosyltransferases, Gene Expression Regulation: Enzymologic, Gene Expression Regulation: Plant, Molecular Sequence Data, Phylogeny, Plant Leaves, Plant Proteins, Raffinose, Sequence Analysis: DNA, Sequence Homology: Amino Acid, Tobacco},
	doi = {10.1104/pp.103.036210},
	author = {Esther M Tapernoux-L{\"u}thi and Andreas B{\"o}hm and Felix Keller}
}
@article {Kapteyn:2007p7982,
	title = {Evolution of Cinnamate/p-coumarate carboxyl methyltransferases and their role in the biosynthesis of methylcinnamate},
	journal = {Plant Cell},
	volume = {19},
	number = {10},
	year = {2007},
	month = {Oct},
	pages = {3212{\textendash}29},
	abstract = {Methylcinnamate, which is widely distributed throughout the plant kingdom, is a significant component of many floral scents and an important signaling molecule between plants and insects. Comparison of an EST database obtained from the glandular trichomes of a basil (Ocimum basilicum) variety that produces high levels of methylcinnamate (line MC) with other varieties producing little or no methylcinnamate identified several very closely related genes belonging to the SABATH family of carboxyl methyltransferases that are highly and almost exclusively expressed in line MC. Biochemical characterization of the corresponding recombinant proteins showed that cinnamate and p-coumarate are their best substrates for methylation, thus designating these enzymes as cinnamate/p-coumarate carboxyl methyltransferases (CCMTs). Gene expression, enzyme activity, protein profiling, and metabolite content analyses demonstrated that CCMTs are responsible for the formation of methylcinnamate in sweet basil. A phylogenetic analysis of the entire SABATH family placed these CCMTs into a clade that includes indole-3-acetic acid carboxyl methyltransferases and a large number of uncharacterized carboxyl methyltransferase-like proteins from monocots and lower plants. Structural modeling and ligand docking suggested active site residues that appear to contribute to the substrate preference of CCMTs relative to other members of the SABATH family. Site-directed mutagenesis of specific residues confirmed these findings.},
	keywords = {Amino Acid Sequence, Blotting: Southern, Cinnamates, Evolution: Molecular, Expressed Sequence Tags, Gas Chromatography-Mass Spectrometry, Gene Expression Profiling, Kinetics, Methylation, Methyltransferases, Models: Molecular, Molecular Sequence Data, Molecular Structure, Ocimum basilicum, Phylogeny, Plant Proteins, Protein Isoforms, Proteomics, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology: Amino Acid, Substrate Specificity},
	doi = {10.1105/tpc.107.054155},
	author = {Jeremy Kapteyn and Anthony V Qualley and Zhengzhi Xie and Eyal Fridman and Natalia Dudareva and David R Gang}
}
