Kinetic analysis of the folding of human growth hormone. Influence of disulfide bonds.


We report the results of a stopped-flow kinetic evaluation of the folding of human growth hormone (hGH). The results are compared with those obtained for a disulfide-modified analog in which the four cysteine residues have been reduced and alkylated to form tetra-S-carbamidomethylated hGH in order to elucidate the role of disulfide bonds in the folding reaction. Multiple detection techniques were applied to monitor both refolding and unfolding processes initiated by guanidine hydrochloride concentration jumps. Using far-UV circular dichroism (CD) detection to monitor folding of hGH, we find that 70% of the secondary structure forms in a burst phase occurring within the stopped-flow dead time. Two slower phases were identified in the observable portion of the CD signal. Multiple kinetic phases were resolved when folding was monitored by intrinsic tryptophan fluorescence or near-UV absorbance as probes of tertiary structure, and the number of time constants required to fit the data depended on the hGH concentration and nature of the denaturant jump. The associated amplitudes also displayed strong dependence on the final denaturant concentration. Results obtained from the tetra-S-carbamidomethylated hGH studies demonstrate that the folding reactions of hGH are remarkably similar in the presence and absence of the disulfide bonds. Disulfide bond reduction in hGH is proposed to affect folding primarily by increasing the population of self-associated intermediate states in the folding pathway. Study holds ProTherm entries: 5200, 5201 Extra Details: cysteine; disulfide bonds; secondary structure;,intermediate states; folding pathway

Submission Details

ID: m8KGbzdt3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:29 p.m.

Version: 1

Publication Details
Youngman KM;Spencer DB;Brems DN;DeFelippis MR,J. Biol. Chem. (1995) Kinetic analysis of the folding of human growth hormone. Influence of disulfide bonds. PMID:7649991
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
200.0 B,C Somatotropin P10912 GHR_HUMAN
190.2 B,C Somatotropin Q9XSZ1 GHR_PAPAN
185.4 B,C Somatotropin P79194 GHR_MACMU
181.4 B,C Somatotropin Q95ML5 GHR_SAIBB
100.0 A Somatotropin P01241 SOMA_HUMAN
100.0 A Somatotropin P58756 SOMA_PANTR
96.8 A Somatotropin P33093 SOMA_MACMU
93.7 A Somatotropin P58757 SOM2_PANTR
90.5 A Somatotropin Q9GMB3 SOMA_CALJA
93.2 A Somatotropin P01242 SOM2_HUMAN
90.5 A Somatotropin P58343 SOMA_SAIBB