Physico-chemical characterization of human von Ebner gland protein expressed in Escherichia coli: implications for its physiological role.
The human von Ebner gland protein (VEG) was expressed in Escherichia coli and purified to homogeneity. The sequence and mass of the recombinant protein were confirmed, and far and near UV circular dichroic analyses showed that the protein was properly folded. The secondary structure of recombinant VEG consisted of 75% beta-sheets and 12% alpha-helices, and it was found to be stable under acidic conditions, in the presence of alcohol, and at high temperatures. The denaturation temperature was 79 degreesC at pH 3.5, with a denaturation enthalpy (DeltaHd) of 160,600 J/mol. Fluorescence analysis and measurement of the denaturation temperature by circular dichroism did not detect any interaction between VEG and extremely bitter (denatonium benzoate, caffein) or sweet (aspartame) compounds. These results suggest that VEG may not function as a shuttle for transfer of sapid molecules to taste receptors.
Creuzenet
C
C
Inra-Leima, Nantes Cedex 03, 44316, France. creuzene@micro.uoguelph.ca
Mangroo
D
D
D001218:Aspartame / Q000378:metabolism; D002110:Caffeine / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D004926:Escherichia coli / Q000235:genetics; D005453:Fluorescence; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D006863:Hydrogen-Ion Concentration; D054835:Lipocalin 1; D011485:Protein Binding / Q000502:physiology; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry*; D013650:Taste Buds / Q000502:physiology; D013696:Temperature; D013816:Thermodynamics
D002352:Carrier Proteins; C518443:LCN1 protein, human; D054835:Lipocalin 1; D000644:Quaternary Ammonium Compounds; D011994:Recombinant Proteins; D002110:Caffeine; C043414:denatonium; D001218:Aspartame