Thermostabilization of Bacillus amyloliquefaciens alpha-amylase by chemical cross-linking.
Chemical cross-linking of a mesophilic alpha-amylase from Bacillus amyloliquefaciens (BAA) was carried out. Intra-molecular cross-links between lysine residues upon treatment of the enzyme with ethylene glycol bis(succinic acid N-hydroxy succinimide ester) resulted in enhancement of thermostability as indicated by irreversible thermoinactivation experiments. Enhancement of thermostability coincided with a dramatic protection against aggregation, combined with a decrease in surface hydrophobicity. Deamidation, another important mechanism of irreversible thermoinactivation, was also diminished upon modification. While no significant changes in the kinetic parameters are evident, rigidification of the protein structure is suggested by circular dichroism (CD) and fluorescence studies.
Habibi
Azadeh Ebrahim
AE
Institute of Biochemistry and Biophysics, University of Tehran, P.O. Box 13145-1384, Tehran, Iran.
Khajeh
Khosro
K
Naderi-Manesh
Hossein
H
Ranjbar
Bijan
B
Nemat-Gorgani
Mohsen
M
D001407:Bacillus / Q000201:enzymology*; D003432:Cross-Linking Reagents / Q000737:chemistry / Q000494:pharmacology*; D004795:Enzyme Stability / Q000187:drug effects; D006358:Hot Temperature; D008239:Lysine / Q000737:chemistry*; D017434:Protein Structure, Tertiary; D000516:alpha-Amylases / Q000737:chemistry*
D003432:Cross-Linking Reagents; D000516:alpha-Amylases; D008239:Lysine