Enzymatic ligation for synthesis of single-chain analogue of monellin by transglutaminase.
Monellin, a sweet protein, consists of two noncovalently associated polypeptide chains: an A chain of 44 amino acid residues and a B chain of 50 residues. Microbial transglutaminase (MTGase) was used for ligation of the monellin subunits without any protecting groups, and without activation of the C alpha-carboxyl group at the C-terminus. Since a peptide fragment LLQG is a good substrate for MTGase to form an amide bond between the gamma-amide group of the Gln residue and the epsilon-amino group of Lys, a monellin B chain analogue in which LLQG was elongated at the C-terminus (B-LLQG) was synthesized by solid-phase synthesis. The monellin A chain analogue in which KGK was elongated at the N-terminus (KGK-A) was synthesized by the same method as that of the B chain analogue. The KGK-A chain and the B-LLQG chain were coupled by MTGase to give single-chain analogue of monellin. The single-chain analogue of monellin was characterized by analytical reverse phase high performance liquid chromatography, electrospray ionization, and amino acid analyses. All analyses gave satisfactory results. The single-chain analogue of monellin was more heat stable than natural monellin.
Ota
M
M
Food Research and Development Laboratories, Ajinomoto Co., Inc., Kawasaki, Japan. flr_oota@tell.ajinomoto.co.jp
Sawa
A
A
Nio
N
N
Ariyoshi
Y
Y
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D010940:Plant Proteins / Q000138:chemical synthesis* / Q000737:chemistry*; D013329:Structure-Activity Relationship; D013549:Sweetening Agents / Q000138:chemical synthesis / Q000737:chemistry; D011503:Transglutaminases
D007202:Indicators and Reagents; D010446:Peptide Fragments; D010940:Plant Proteins; D013549:Sweetening Agents; C002541:monellin protein, Dioscoreophyllum cumminsii; D011503:Transglutaminases