Characterization of the sweet‐tasting protein from <i>Dioscoreophyllum cumminsii</i> (Stapf) Diels

Wel, H. van der; Loeve, Kees

doi:10.1016/0014-5793(73)80556-3

Cited by 25 publications

(10 citation statements)

References 10 publications

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“…However, later investigators showed that the sweet principle of D. cumminsii was a protein. 45 - 235 Morris et al (1973) 46 termed this sweet protein monellin (after their institution of affiliation), and found that this compound had a molecular weight of 10,700, and consisted of a single polypeptide chain of 91 amino acid residues. Morris, 2 Cagan et al, 236 and Higginbotham 232 have described in detail studies contributing to the purification and characterization of this interesting substance.…”

Section: B Monellinmentioning

confidence: 97%

Sweetening agents of plant origin*

Kinghora

Soejarto

Inglett

1986

Critical Reviews in Plant Sciences

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Section: B Monellinmentioning

confidence: 97%

Sweetening agents of plant origin*

Kinghora

Soejarto

Inglett

1986

Critical Reviews in Plant Sciences

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“…Non-carbohydrate sweet-tasting substances include several chemically distinct groups of small molecule artificial sweeteners, such as sucralose, saccharin, cyclamate, and acesulfame K, as well as dipeptide sweeteners, such as aspartame and neotame. Sweet-tasting proteins have been found as naturally occurring molecules from plants (or rarely from animals) including thaumatin 1, monellin 2, mabinlin 3, brazzein 4; 5, eggwhite lysozyme 6, and curculin/neoculin 7. In addition, a pure sweet-antagonist protein, the glycoprotein RBP from chicken egg, has been reported to inhibit specifically the taste of sweet-protein but not carbohydrates or artificial sweeteners 8…”

Section: Introductionmentioning

confidence: 99%

Key Amino Acid Residues Involved in Multi-Point Binding Interactions between Brazzein, a Sweet Protein, and the T1R2–T1R3 Human Sweet Receptor

Assadi‐Porter

Maillet

Radek

et al. 2010

Journal of Molecular Biology

105

106

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The sweet protein brazzein activates the human sweet receptor, a heterodimeric G-protein coupled receptor (GPCR) composed of subunits T1R2 and T1R3. In order to elucidate the key amino acid(s) responsible for this interaction, we mutated residues in brazzein and each of the two subunits of the receptor. The effects of brazzein mutations were assayed by a human taste panel and by an in vitro assay involving receptor subunits expressed recombinantly in human embryonic kidney cells; the effects of the receptor mutations were assayed by the in vitro assay. We mutated surface residues of brazzein at three putative interaction sites: Site 1 (Loop43), Site 2 (N-and C-terminus and adjacent Glu36, Loop33), and Site 3 (Loop9-19). Basic residues in Site 1 and acidic residues in Site 2 were essential for positive responses from each assay. Mutation of Y39A (Site 1) greatly reduced positive responses. A bulky side chain at position 54 (Site 2), rather than a side chain with hydrogen bonding potential, was required for positive responses as was the presence of the native disulfide bond in Loop 9-19 (Site 3). Results from mutagenesis and chimeras of the receptor indicated that brazzein interacts with both T1R2 and T1R3 and that the Venus fly trap module of T1R2 is important for brazzein agonism. With one exception, all mutations of receptor residues at putative interaction sites predicted by wedge models failed to yield the expected decrease in the brazzein response. The exception, hT1R2:R217A-hT1R3, which contained a substitution in lobe 2 at the interface between the two subunits, exhibited a small selective decrease in brazzein activity. However, because the mutation was found to increase the positive cooperativity of binding by multiple ligands proposed to bind both T1R subunits (brazzein, monellin, and sucralose) but not those that bind to a single subunit (neotame and cyclamate), we suggest that this site in involved in subunit-subunit interaction rather than direct brazzein binding. Results from this study support a multipoint interaction between brazzein and the sweet receptor by some mechanism other than the proposed wedge models.

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“…This distribution of the aromatic amino acids allows the fluorescence emission spectrum of monellin to reflect changes in conformation (6). Studies of monellin under various conditions have led to the conclusion that its biological activity, sweetness, is dependent upon the tertiary and quaternary structures of the protein ( 1-3, Monellin is labile to traditional protein denaturants such as urea, guanidine hydrochloride, high temperature, and extremes of pH (1,3,(6)(7)(8)(9)(10)(11)(12)(13). The extent to which the sweet taste of the protein is altered by these 6-1 3).…”

mentioning

confidence: 99%

Conformational Changes of the Sweet Protein Monellin as Measured by Fluorescence Emission

Brand¹,

Çağan²,

Bayley³

1985

Experimental Biology and Medicine

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Monellin is a protein that tastes sweet. In the native state it is a dimer composed of two dissimilar noncovalently associated polypeptides. The conformation of the protein is a determinant of its sweetness, and the present investigation takes advantage of the fluorescence spectrum being a sensitive index of its conformation. The emission spectrum is used to evaluate the ability of temperature and pH to alter the conformation and the sweetness of the protein.When monellin dissolved in water is heated in discrete steps from 25 to 100°C, its sweetness decreases. The halfwidth of the fluorescence emission band increases in parallel with the loss of sweetness. The increase in halfwidth is due primarily to an increase in the intensity of tyrosine emission that may be the result of the two dissimilar polypeptides of monellin begnning to separate. Tyrosine residues are present in both chains, while the single tryptophan occurs in only one. Monellin is less susceptible to denaturation by increasing temperature when dissolved in sodium acetate buffer at pH 4 than it is at pH 3 or 7. When the pH of a solution containing monellin in 0.1 M KCI is vaned from 2 to 13, there is a broad pH range (pH 4 to 9) where monellin's conformation is not markedly altered. Below pH 3.5 and above pH 10.5, however, the emission spectra indicate that substantial denaturation occurs. However, monellin can be partially renatured following pH 12 treatment with only minimal loss of sweetness. The sweetness of monellin under these two types of denaturing conditions, temperature and pH, can be predicted by the fluorescence emission spectrum of the protein. In addition, this study confirms that the biological activity of monellin, its sweetness, is a function of quaternary Structure O f the protein. 62

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Characterization of the sweet‐tasting protein from Dioscoreophyllum cumminsii (Stapf) Diels

Cited by 25 publications

References 10 publications

Sweetening agents of plant origin*

Sweetening agents of plant origin*

Key Amino Acid Residues Involved in Multi-Point Binding Interactions between Brazzein, a Sweet Protein, and the T1R2–T1R3 Human Sweet Receptor

Conformational Changes of the Sweet Protein Monellin as Measured by Fluorescence Emission

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