Comparative study of the stability of the folding intermediates of the calcium-binding lysozymes.
Unfolding profiles of two calcium-binding lysozymes, equine milk lysozyme and pigeon egg-white lysozyme, were obtained by circular dichroism and proton NMR measurements. Equine lysozyme unfolds through a stable molten globule intermediate. The molten globule of equine lysozyme was characterized as more ordered than that of bovine alpha-lactalbumin. On the other hand, pigeon lysozyme unfolds by a two-state mechanism and the intermediate could not be observed in guanidine or thermal unfolding, the same as with conventional non-calcium-binding lysozymes. Thus, from the point of view of the unfolding profile, equine lysozyme belongs to the group of alpha-lactalbumin, but pigeon lysozyme belongs to the conventional lysozyme group.
Nitta
K
K
Department of Polymer Science, Faculty of Science, Hokkaido University, Japan.
Tsuge
H
H
Iwamoto
H
H
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002942:Circular Dichroism; D010856:Columbidae; D004795:Enzyme Stability; D005260:Female; D019791:Guanidine; D006146:Guanidines; D006736:Horses; D009682:Magnetic Resonance Spectroscopy; D008892:Milk / Q000201:enzymology; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D010063:Ovum / Q000201:enzymology; D017510:Protein Folding; D013045:Species Specificity
D006146:Guanidines; D009113:Muramidase; D019791:Guanidine; D002118:Calcium