Disulfide bridge structure of the heat-stable sweet protein mabinlin II.
The heat-stable sweet protein mabinlin was composed of a A-chain of 33 amino-acid residues and a B-chain of 72 amino-acid residues (Liu, X., Maeda, S., Hu, Z., Aiuchi, T., Nakaya, K. and Kurihara, Y. (1993) Eur. J. Biochem. 211, 281-287). A-chain and B-chain contain two and six cysteine residues, respectively. The formation of two interchain disulfide bridges at Cys(A5)-Cys(B21) and Cys(A18)-Cys(B10), and two intrachain disulfide bridges at Cys(B11)-Cys(B59) and Cys(B23)-Cys(B67) were determined by amino-acid sequencing and composition analysis of cystine-containing peptides isolated by HPLC. Cleavage of the disulfide bridges with dithiothreitol results in complete loss of the sweet activity of mabinlin II. It was suggested that the structure fixed by four disulfide bridges contributes to heat stability of mabinlin II.
Department of Chemistry, Faculty of Education, Yokohama National University, Japan.
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Nirasawa
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Liu
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Nishino
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Kurihara
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D004220:Disulfides / Q000737:chemistry*; D004229:Dithiothreitol; D004355:Drug Stability; D006358:Hot Temperature; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010446:Peptide Fragments / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry*; D013649:Taste; D013820:Thermolysin; D014357:Trypsin
D000596:Amino Acids; D004220:Disulfides; D010446:Peptide Fragments; D010940:Plant Proteins; C083584:mabinlin protein, Capparis masaikai; D014357:Trypsin; D013820:Thermolysin; D004229:Dithiothreitol