Thermodynamics and kinetics of folding of common-type acylphosphatase: comparison to the highly homologous muscle isoenzyme.


The thermodynamics and kinetics of folding of common-type acylphosphatase have been studied under a variety of experimental conditions and compared with those of the homologous muscle acylphosphatase. Intrinsic fluorescence and circular dichroism have been used as spectroscopic probes to follow the folding and unfolding reactions. Both proteins appear to fold via a two-state mechanism. Under all the conditions studied, common-type acylphosphatase possesses a lower conformational stability than the muscle form. Nevertheless, common-type acylphosphatase folds more rapidly, suggesting that the conformational stability and the folding rate are not correlated in contrast to recent observations for a number of other proteins. The unfolding rate of common-type acylphosphatase is much higher than that of the muscle enzyme, indicating that the differences in conformational stability between the two proteins are primarily determined by differences in the rate of unfolding. The equilibrium m value is markedly different for the two proteins in the pH range of maximum conformational stability (5. 0-7.5); above pH 8.0, the m value for common-type acylphosphatase decreases abruptly and becomes similar to that of the muscle enzyme. Moreover, at pH 9.2, the dependencies of the folding and unfolding rate constants of common-type acylphosphatase on denaturant concentration (mf and mu values, respectively) are notably reduced with respect to pH 5.5. The pH-induced decrease of the m value can be attributed to the deprotonation of three histidine residues that are present only in the common-type isoenzyme. This would decrease the positive net charge of the protein, leading to a greater compactness of the denatured state. The folding and unfolding rates of common-type acylphosphatase are not, however, significantly different at pH 5.5 and 9.2, indicating that this change in compactness of the denatured and transition states does not have a notable influence on the rate of protein folding. Study holds ProTherm entries: 5668, 5669, 5670, 5671, 5672, 5673, 5674, 5675, 5676, 5677 Extra Details: intrinsic fluorescence; two-state mechanism;,conformational stability; isoenzyme; protein folding

Submission Details

ID: X9ksjRoQ3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:30 p.m.

Version: 1

Publication Details
Taddei N;Chiti F;Paoli P;Fiaschi T;Bucciantini M;Stefani M;Dobson CM;Ramponi G,Biochemistry (1999) Thermodynamics and kinetics of folding of common-type acylphosphatase: comparison to the highly homologous muscle isoenzyme. PMID:10026297
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 Acylphosphatase-1 P07311 ACYP1_HUMAN
91.9 Acylphosphatase-1 P24540 ACYP1_PIG
90.9 Acylphosphatase-1 P56376 ACYP1_MOUSE
100.0 Acylphosphatase-2 P00818 ACYP2_HORSE
96.9 Acylphosphatase-2 P00819 ACYP2_PIG
94.9 Acylphosphatase-2 P07033 ACYP2_BOVIN
94.9 Acylphosphatase-2 P14621 ACYP2_HUMAN
93.9 Acylphosphatase-2 P00820 ACYP2_RABIT
91.8 Acylphosphatase-2 P35744 ACYP2_CAVPO