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Structure and dynamic studies by NMR of the potent sweet protein monellin and a non‐sweet analog
Author(s) -
Mizukoshi Toshimi,
Kohmura Masanori,
Suzuki Ei-ichiro,
Ariyoshi Yasuo
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00945-9
Subject(s) - chemistry , flexibility (engineering) , side chain , nuclear magnetic resonance spectroscopy , peptide , stereochemistry , amino acid residue , amino acid , biochemistry , peptide sequence , organic chemistry , statistics , mathematics , gene , polymer
Monellin, an intensely sweet protein and a non‐sweet analog in which the Asp B7 in monellin has been replaced with Abu B7 were studied by NMR. The results of our investigations show that the 3‐dimensional structure of these two proteins are very similar indicating that the lack of the β‐carboxyl group in the Abu B7 analog is responsible for the loss of sweet potency. Selectively labeled monellin was prepared by solid‐phase peptide synthesis by incorporating 15 N‐labeled amino acids into 10 key positions including Asp B7 . The internal mobility of these 10 key residues in monellin was estimated by the method of model‐free analyses and our NMR studies show that Asp B7 is the most flexible of these 10 residues. The flexibility of the Asp B7 side chain may be important for receptor binding.