Stability of the molten globule state of a domain-exchanged chimeric protein between human and bovine alpha-lactalbumins.

A domain-exchanged chimeric alpha-lactalbumin (alpha-LA), which consisted of the alpha-domain of human alpha-LA and the beta-domain of bovine alpha-LA, was constructed. Like native alpha-LA, the chimeric protein was in a molten globule state in the absence of Ca(2+) at neutral pH and low salt concentration. The stability of the molten globule state of the constructed chimeric protein was identical to that of the recombinant human protein and was higher than that of the recombinant bovine protein. The stability of the molten globule state of alpha-LA is defined by the stability of the alpha-domain.