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| | ==Crystal structure of a single chain monellin mutant (Y65R) pH 2.0== | | ==Crystal structure of a single chain monellin mutant (Y65R) pH 2.0== |
| - | <StructureSection load='5o7k' size='340' side='right' caption='[[5o7k]], [[Resolution|resolution]] 2.05Å' scene=''> | + | <StructureSection load='5o7k' size='340' side='right'caption='[[5o7k]], [[Resolution|resolution]] 2.05Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[5o7k]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Diocu Diocu]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5O7K OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5O7K FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[5o7k]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Dioscoreophyllum_cumminsii Dioscoreophyllum cumminsii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5O7K OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5O7K FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.05Å</td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[5lc6|5lc6]], [[5lc7|5lc7]]</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr> |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=5o7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5o7k OCA], [http://pdbe.org/5o7k PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=5o7k RCSB], [http://www.ebi.ac.uk/pdbsum/5o7k PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=5o7k ProSAT]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=5o7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5o7k OCA], [https://pdbe.org/5o7k PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5o7k RCSB], [https://www.ebi.ac.uk/pdbsum/5o7k PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5o7k ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/MONB_DIOCU MONB_DIOCU]] Taste-modifying protein; intensely sweet-tasting protein. | + | [https://www.uniprot.org/uniprot/MONB_DIOCU MONB_DIOCU] Taste-modifying protein; intensely sweet-tasting protein.[https://www.uniprot.org/uniprot/MONA_DIOCU MONA_DIOCU] Taste-modifying protein; intensely sweet-tasting protein. |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Diocu]] | + | [[Category: Dioscoreophyllum cumminsii]] |
| - | [[Category: Merlino, A]] | + | [[Category: Large Structures]] |
| - | [[Category: Pica, A]] | + | [[Category: Merlino A]] |
| - | [[Category: Plant protein]] | + | [[Category: Pica A]] |
| - | [[Category: Sweet protein]]
| + | |
| - | [[Category: Sweetener]]
| + | |
| Structural highlights
Function
MONB_DIOCU Taste-modifying protein; intensely sweet-tasting protein.MONA_DIOCU Taste-modifying protein; intensely sweet-tasting protein.
Publication Abstract from PubMed
BACKGROUND: MNEI and its variant Y65R-MNEI are sweet proteins with potential applications as sweeteners in food industry. Also, they are often used as model systems for folding and aggregation studies. METHODS: X-ray crystallography was used to structurally characterize Y65R-MNEI at five different pHs, while circular dichroism and fluorescence spectroscopy their thermal and chemical stability. ThT assay and AFM were used for studying the kinetics of aggregation and morphology of the aggregates. RESULTS: Crystal structures of Y65R-MNEI revealed the existence of a dimer in the asymmetric unit, which, depending on the pH, assumes either an open or a closed conformation. The pH dramatically affects kinetics of formation and morphology of the aggregates: both MNEI and Y65R-MNEI form fibrils at acidic pH while amorphous aggregates are observed at neutral pH. CONCLUSIONS: The mutation Y65R induces structural modifications at the C-terminal region of the protein, which account for the decreased stability of the mutant when compared to MNEI. Furthermore, the pH-dependent conformation of the Y65R-MNEI dimer may explain the different type of aggregates formed as a function of pH. General Significance The investigation of the structural bases of aggregation gets us closer to the possibility of controlling such process, either by tuning the physicochemical environmental parameters or by site directed mutagenesis. This knowledge is helpful to expand the range of stability of proteins with potential industrial applications, such as MNEI and its mutant Y65R-MNEI, which should ideally preserve their structure and soluble state through a wide array of conditions. Classification structure-function relationship, protein stability, protein aggregation.
pH driven fibrillar aggregation of the super-sweet protein Y65R-MNEI: a step-by-step structural analysis.,Pica A, Leone S, Di Girolamo R, Donnarumma F, Emendato A, Rega MF, Merlino A, Picone D Biochim Biophys Acta. 2017 Dec 27. pii: S0304-4165(17)30400-2. doi:, 10.1016/j.bbagen.2017.12.012. PMID:29288772[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Pica A, Leone S, Di Girolamo R, Donnarumma F, Emendato A, Rega MF, Merlino A, Picone D. pH driven fibrillar aggregation of the super-sweet protein Y65R-MNEI: a step-by-step structural analysis. Biochim Biophys Acta. 2017 Dec 27. pii: S0304-4165(17)30400-2. doi:, 10.1016/j.bbagen.2017.12.012. PMID:29288772 doi:http://dx.doi.org/10.1016/j.bbagen.2017.12.012
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