Structural basis for the difference in thermodynamic properties between the two cysteine proteinase inhibitors human stefins A and B.

Abstract

Homology modelling has been used to model stefin A based on the X-ray structure of stefin B. Several models have been produced by interactive modelling or positioning of the side chains by Monte Carlo procedure with simulated annealing. The quality of models was evaluated by calculation of the free energy of hydration, 3D-1D potential or buried area of surface accessibility. Stefin A is a thermostable protein, exhibiting a two-state denaturation, while stefin B denatures at a 40 degrees C lower temperature and forms a stable molten globule intermediate under mild denaturing conditions. From the tertiary structures, thermodynamic functions were predicted, conforming closely to the experimental calorimetric results. Polar and apolar buried areas of surface accessibility were obtained by structural deconvolution of the thermograms. It is suggested that the basic difference between the stefins is the domination of hydrophobic interaction in the stabilization of stefin B, which is due to its non-specific nature leading to the formation of a molten globule intermediate. Modelling of stefin A predicts increased numbers of hydrogen bonds which stabilize it and increase the cooperativity of its denaturation. Study holds ProTherm entries: 10933, 10934 Extra Details: cysteine proteinase inhibitor; homology modelling;,molten globule; structural thermodynamics; thermostability

Submission Details

ID: jNybB7eD3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:41 p.m.

Version: 1

Publication Details
Jerala R;Zerovnik E;Lohner K;Turk V,Protein Eng. (1994) Structural basis for the difference in thermodynamic properties between the two cysteine proteinase inhibitors human stefins A and B. PMID:7809037
Additional Information

Study Summary

Number of data points 6
Proteins Cystatin-A ; Cystatin-A ; Papain ; Cystatin-B
Unique complexes 2
Assays/Quantities/Protocols Experimental Assay: dCp pH:5.3, buffers:acetate: 20 mM, prot_conc:1.2 mg/mL ; Experimental Assay: dHcal pH:5.3, buffers:acetate: 20 mM, prot_conc:1.2 mg/mL ; Experimental Assay: Tm pH:5.3, buffers:acetate: 20 mM, prot_conc:1.2 mg/mL ; Experimental Assay: dCp pH:8.1, buffers:Tris-HCl: 20 mM, prot_conc:1 mg/mL ; Experimental Assay: dHcal pH:8.1, buffers:Tris-HCl: 20 mM, prot_conc:1 mg/mL ; Experimental Assay: Tm pH:8.1, buffers:Tris-HCl: 20 mM, prot_conc:1 mg/mL
Libraries Mutations for sequence MIPGGLSEAKPATPEIQEIVDKVKPQLEEKTNETYGKLEAVQYKTQVVAGTNYYIKVRAGDNKYMHLKVFKSLPGQNEDLVLTGYQVDKNKDDELTGF ; Mutations for sequence E:IPEYVDWRQKGAVTPVKNQGSCGSCWAFSAVVTIEGIIKIRTGNLNQYSEQELLDCDRRSYGCNGGYPWSALQLVAQYGIHYRNTYPYEGVQRYCRSREKGPYAAKTDGVRQVQPYNQGALLYSIANQPVSVVLQAAGKDFQLYRGGIFVGPCGNKVDHAVAAVGYGPNYILIKNSWGTGWGENGYIRIKRGTGNSYGVCGLYTSSFYPVKN/I:MMSGAPSATQPATAETQHIADQVRSQLEEKYNKKFPVFKAVSFKSQVVAGTNYFIKVHVGDEDFVHLRVFQSLPHENKPLTLSNYQTNKAKHDELTYF

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 Cystatin-A P01040 CYTA_HUMAN
100.0 Cystatin-B Q76LA0 CYTB_GORGO
100.0 Cystatin-B P04080 CYTB_HUMAN
100.0 Cystatin-B P60575 CYTB_PANPA
100.0 Cystatin-B P60576 CYTB_PONPY
99.0 Cystatin-B Q8I030 CYTB_PANTR
94.9 Cystatin-B Q862Z5 CYTB_MACFU
98.6 E Papain P00784 PAPA1_CARPA