Enhancing the thermostability of glucose isomerase by protein engineering.
We have engineered recombinant glucose isomerase (GI) from Actinoplanes missouriensis by site-directed mutagenesis to enhance its thermal stability in both the soluble and immobilized forms. Substitution of arginine for lysine at position 253, which lies at the dimer/dimer interface of the GI tetramer, produced the largest stabilization under model industrial conditions. We discuss our results in terms of a model in which chemical glycation of lysines by sugars in the industrial corn syrup substrate represents a major pathway of destabilization.
Quax
W J
WJ
Gist-brocades, Research & Development, Delft, The Netherlands.
Mrabet
N T
NT
Luiten
R G
RG
Schuurhuizen
P W
PW
Stanssens
P
P
Lasters
I
I
D019747:Aldose-Ketose Isomerases; D002238:Carbohydrate Epimerases / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D004800:Enzymes, Immobilized; D004926:Escherichia coli / Q000235:genetics; D006094:Gram-Positive Bacteria / Q000201:enzymology / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D016296:Mutagenesis; D015202:Protein Engineering; D012996:Solutions; D013816:Thermodynamics
D004800:Enzymes, Immobilized; D012996:Solutions; D002238:Carbohydrate Epimerases; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase