Denaturant-induced unfolding of the acetyl-esterase from Escherichia coli.
The stability of acetyl-esterase, Aes, from Escherichia coli against the denaturing action of urea and guanidine hydrochloride, GuHCl, has been investigated by means of circular dichroism and fluorescence measurements. The urea-induced unfolding curves show a single inflection point at 6.2 M urea, whereas the GuHCl-induced curves show two inflection points at 1.4 and 3.1 M GuHCl. The unfolding process is reversible with both urea and GuHCl. These results, together with similar experimental data on the mutant form V20D-Aes, suggest the presence of two domains in the Aes structure, which unfold more or less independently depending on the denaturant used. This is also supported by a 3D model obtained by homology modeling using the structure of brefeldine as a template. The effect of NaCl on the urea-induced unfolding curves of the enzyme has also been investigated.
Del Vecchio
Pompea
P
Department of Chemistry, University of Naples Federico II, Italy. delvecchio@chemistry.unina.it
Graziano
Giuseppe
G
Granata
Vincenzo
V
Farias
Tiziana
T
Barone
Guido
G
Mandrich
Luigi
L
Rossi
Mosè
M
Manco
Giuseppe
G
D000115:Acetylesterase / Q000737:chemistry* / Q000235:genetics; D001224:Aspartic Acid / Q000235:genetics; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry; D002942:Circular Dichroism; D004795:Enzyme Stability / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D019791:Guanidine; D008958:Models, Molecular; D017354:Point Mutation; D011489:Protein Denaturation; D017510:Protein Folding; D017434:Protein Structure, Tertiary / Q000235:genetics; D012965:Sodium Chloride; D013050:Spectrometry, Fluorescence; D040681:Structural Homology, Protein; D013816:Thermodynamics; D014508:Urea; D014633:Valine / Q000235:genetics
D029968:Escherichia coli Proteins; D001224:Aspartic Acid; D012965:Sodium Chloride; D014508:Urea; D002265:Carboxylic Ester Hydrolases; C085832:brefeldin A esterase; D000115:Acetylesterase; D014633:Valine; D019791:Guanidine