Cold denaturation of the molten globule states of apomyoglobin and a profile for protein folding.


Protein folding is a process in which an extended polypeptide chain acquires compact packing through the formation of specific secondary and tertiary structures and hydrophobic interactions. Although much attention has been paid to secondary and tertiary structures, there is no definitive view about the relationship between these structures, compactness, and hydrophobic interactions during the process of protein folding. We show here that the molten globule intermediates of horse apomyoglobin exhibit cold denaturation in addition to heat denaturation, which indicates that the heat capacity change upon unfolding is positive and significant. This demonstrates a small but distinct contribution of hydrophobic interactions to the stability of the molten globule state. We determined the radius of gyration of the various conformational states of horse apomyoglobin and holomyoglobin by measuring small angle X-ray scattering. By comparing the conformational states in terms of secondary structure, radius of gyration, and change in heat capacity upon unfolding, we constructed a folding profile. The profile shows that the protein becomes more compact with formation of the secondary structure, but does not form substantial hydrophobic interactions until a later rate-limiting stage when tight packing of the protein side chains occurs. A very similar profile was also obtained with horse cytochrome c. We propose that the folding profile obtained with these proteins will be common to many globular proteins. Study holds ProTherm entries: 4440, 4441, 4442 Extra Details: compact packing; hydrophobic interactions; molten globule state;,radius of gyration; folding profile

Submission Details

ID: njok4UkD

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:25 p.m.

Version: 1

Publication Details
Nishii I;Kataoka M;Tokunaga F;Goto Y,Biochemistry (1994) Cold denaturation of the molten globule states of apomyoglobin and a profile for protein folding. PMID:8161550
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Myoglobin P68083 MYG_EQUBU
100.0 Myoglobin P68082 MYG_HORSE
91.6 Myoglobin P02181 MYG_INIGE
92.2 Myoglobin P02169 MYG_LEPMU
90.9 Myoglobin P02166 MYG_PERPO
90.9 Myoglobin P02189 MYG_PIG
90.8 Myoglobin Q0KIY1 MYG_BALBO
90.8 Myoglobin Q0KIY2 MYG_BALED
90.8 Myoglobin P02177 MYG_ESCRO
90.3 Myoglobin P02183 MYG_MESCA
90.3 Myoglobin Q0KIY0 MYG_MESST
90.3 Myoglobin P02167 MYG_NYCCO
90.3 Myoglobin P02165 MYG_TUPGL
90.9 Myoglobin P11343 MYG_LUTLU
90.3 Myoglobin P02163 MYG_ROUAE
90.1 Myoglobin P02178 MYG_MEGNO