Single-chain monellin

An engineered single-chain monellin (SCM) constructed by fusing the two chains, A and B, covalently has been proved to retain all of the sweetening power and has a greater thermal stability.SCM was studied by NMR both in solution (Fig. and in the solid-state. Several SCM mutants were... 

Monellin can be purified from the fruit of Dioscoreophyllum cumminsii grown in West Africa and is approximately 100 000 times sweeter than sugar on a molar basis and several thousand times sweeter on a weight basis.Single-chain monellin (SCM), which is an engineered 94-residue polypeptide, has proven to be as the sweet as native two-chain monellin. It is more stable than the native monellin at high temperature and in acidic... 

Single-chain Monellin (= MNEI Monellin B-Gly-Phe-Monellin A)] (94 aa, lOkDa protein) Synthetic Sweet ( = Monellin)... 

Lee, S.Y., Lee, J.H., Chang, H.J., Cho, J.M., Jung, J.W., and Lee, W. (1999). Solution structure of a sweet protein single-chain monellin determined by nuclear magnetic resonance and dynamical simulated annealing calculations. Biochemistry 38, 2340-2346. 

Brazzein is another small sweet-tasting protein whose solution structure has been recently solved by NMR. Brazzein tastes 2000 times sweeter than sucrose on a weight basis and is exceptionally thermostable. As indicated by NMR, the structure of this 54 residue, single-chain polypeptide does not change between 32 and 82 °C and retains its sweetness after incubation at 98 °C for two hours.Brazzein contains one a-helix and three strands of antiparallel jd-sheet stabilized by four intramolecular disulphide bonds. It has been proposed that the disulphide bonds could be responsible for the thermostability of brazzein by forming a compact structure at the tertiary level.The structure of brazzein does not resemble that of the other two sweet proteins with known structures, monellin and thaumatin, whereas sequence alignment and structural prediction indicate that brazzein shares the fold of a newly identified family of serine proteinase inhibitors. 

Monellin, an intensively sweet protein from the West African berries Dioscoreophyllum cumminsii. On a weight basis, monellin is several thousand times more potent in sweetness than sucrose. It consists of two non-covalently associated polypeptide chains, A and B, with 44 and 50 residues, respectively. According to the X-ray crystal structure, the natural protein consists of an anti-parallel /S-sheet with five strands and an a-hdix. Single-chain moneUin (SCM), an engineered 94 aa polypeptide, has been proven to be as sweet as the native two-chain molecule, and is more stable in both high-temperature and acidic environments compared to the native monellin [T. Mizukoshi et al., FEBS Lett. 1997, 413, 409 ... 

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