ISSN:
1573-4943
Keywords:
Cytochrome b5
;
mutagenesis
;
protein stability
;
folding
;
methanol
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract In order to illustrate the structural importance of proline-40 of cytochrome b5 (Cyt b5), the P40V mutant gene was constructed. Unfolding and refolding of Cyt b5 induced by methanol was investigated by means of the UV-visible spectrum, circular dichroism, and the fluorescence spectrum. Methanol denaturation of Cyt b5 is a cooperative process, that is, the heme group dissociates from the heme pocket accompanied by unfolding of the polypeptide chain both in the secondary and tertiary structures. Substitution of proline by valine reduces the stability of the mutant under methanol denaturation. The unfolding process is almost reversible by dilution. During refolding, the denatured polypeptide must be folded to a more ordered structure prior to the heme capture. Pro40 plays an important role in modulating the protein's stability. The role of tyrosine in the unfolding and refolding of Cyt b5 is evaluated for the first time. A mechanism of methanol denaturation is also proposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1020699200092
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