Onconase: an unusually stable protein.


Several members of the RNase A superfamily are endowed with antitumor activity, showing selective cytotoxicity toward tumor cell lines. One of these is onconase, the smallest member of the superfamily, which at present is undergoing phase-III clinical trials as an antitumor drug. Our investigation focused on other interesting features of the enzyme, such as its unusually high denaturation temperature, its low catalytic activity, and its renal toxicity as a drug. We used differential scanning calorimetry, circular dichroism, fluorescence measurements, and limited proteolysis to investigate the molecular determinants of the stability of onconase and of a mutant, (M23L)-ONC, which is catalytically more active than the wild-type enzyme, and fully active as an antitumor agent. The determination of the main thermodynamic parameters of the protein led to the conclusion that onconase is an unusually stable protein. This was confirmed by its resistance to proteolysis. On the basis of this analysis and on a comparative analysis of the (M23L)-ONC variant of the protein, which is less stable and more sensitive to proteolysis, a model was constructed in line with available data. This model supports a satisfactory hypothesis of the molecular basis of onconase stability and low-catalytic activity. Study holds ProTherm entries: 8561, 8562, 8563, 8564, 8565, 8566, 8567, 8568, 8569, 8570, 8571, 8572, 8573, 8574, 8575, 8576, 8577, 8578, 8579, 8580, 8581, 8582, 8583, 8584, 8585, 8586, 8587, 8588, 8589, 8590, 8591, 8592, 8593, 8594, 8595, 8596, 8597, 8598, 8599, 8600 Extra Details: antitumor activity; catalytic activity; renal toxicity; proteolysis

Submission Details

ID: McNaD98d3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:36 p.m.

Version: 1

Publication Details
Notomista E;Catanzano F;Graziano G;Dal Piaz F;Barone G;D'Alessio G;Di Donato A,Biochemistry (2000) Onconase: an unusually stable protein. PMID:10913282
Additional Information

Study Summary

Number of data points 122
Proteins Protein P-30 ; Protein P-30
Unique complexes 2
Assays/Quantities/Protocols Experimental Assay: Cm ; Experimental Assay: m ; Experimental Assay: dG_H2O ; Experimental Assay: Cm ; Experimental Assay: m ; Experimental Assay: dG_H2O ; Experimental Assay: dG pH:8.0 ; Experimental Assay: dG pH:7.0 ; Experimental Assay: dG pH:6.0 ; Experimental Assay: dG pH:5.0 ; Experimental Assay: dG pH:4.0 ; Experimental Assay: dG pH:3.5 ; Experimental Assay: dG pH:3.0 ; Experimental Assay: dG pH:2.5 ; Experimental Assay: dG pH:2.0 ; Experimental Assay: dCp pH:8.0 ; Experimental Assay: dHcal pH:8.0 ; Experimental Assay: Tm pH:8.0 ; Experimental Assay: dHvH pH:8.0 ; Experimental Assay: dCp pH:7.0 ; Experimental Assay: dHcal pH:7.0 ; Experimental Assay: Tm pH:7.0 ; Experimental Assay: dHvH pH:7.0 ; Experimental Assay: dCp pH:6.0 ; Experimental Assay: dHcal pH:6.0 ; Experimental Assay: Tm pH:6.0 ; Experimental Assay: dHvH pH:6.0 ; Experimental Assay: dCp pH:5.0 ; Experimental Assay: dHcal pH:5.0 ; Experimental Assay: Tm pH:5.0 ; Experimental Assay: dHvH pH:5.0 ; Experimental Assay: dCp pH:4.0 ; Experimental Assay: dHcal pH:4.0 ; Experimental Assay: Tm pH:4.0 ; Experimental Assay: dHvH pH:4.0 ; Experimental Assay: dCp pH:3.5 ; Experimental Assay: dHcal pH:3.5 ; Experimental Assay: Tm pH:3.5 ; Experimental Assay: dHvH pH:3.5 ; Experimental Assay: dCp pH:3.0 ; Experimental Assay: dHcal pH:3.0 ; Experimental Assay: Tm pH:3.0 ; Experimental Assay: dHvH pH:3.0 ; Experimental Assay: dCp pH:2.5 ; Experimental Assay: dHcal pH:2.5 ; Experimental Assay: Tm pH:2.5 ; Experimental Assay: dHvH pH:2.5 ; Experimental Assay: dCp pH:2.0 ; Experimental Assay: dHcal pH:2.0 ; Experimental Assay: Tm pH:2.0 ; Experimental Assay: dHvH pH:2.0 ; Derived Quantity: ddG_H2O ; Derived Quantity: ddG_H2O ; Derived Quantity: ddG pH:8.0 ; Derived Quantity: ddG pH:7.0 ; Derived Quantity: ddG pH:6.0 ; Derived Quantity: ddG pH:5.0 ; Derived Quantity: ddG pH:4.0 ; Derived Quantity: ddG pH:3.5 ; Derived Quantity: ddG pH:3.0 ; Derived Quantity: ddG pH:2.5 ; Derived Quantity: ddG pH:2.0 ; Derived Quantity: dTm pH:8.0 ; Derived Quantity: dTm pH:7.0 ; Derived Quantity: dTm pH:6.0 ; Derived Quantity: dTm pH:5.0 ; Derived Quantity: dTm pH:4.0 ; Derived Quantity: dTm pH:3.5 ; Derived Quantity: dTm pH:3.0 ; Derived Quantity: dTm pH:2.5 ; Derived Quantity: dTm pH:2.0

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 PDB Entries

Structure ID Release Date Resolution Structure Title
1PU3 2003-06-24T00:00:00+0000 0 The Solution NMR Structure and Dynamics of a Recombinant Onconase with Altered N-terminal and Met23 residues
1YV4 2005-02-15T00:00:00+0000 1.51 X-ray structure of M23L onconase at 100K
1YV6 2005-02-15T00:00:00+0000 1.78 X-ray structure of M23L onconase at 298K
1YV7 2005-02-15T00:00:00+0000 1.9 X-ray structure of (C87S,des103-104) onconase
2GMK 2006-04-06T00:00:00+0000 1.65 Crystal structure of onconase double mutant with spontaneously-assembled (AMP) 4 stack
2I5S 2006-08-25T00:00:00+0000 1.9 Crystal structure of onconase with bound nucleic acid
2KB6 2008-11-21T00:00:00+0000 0 Solution structure of onconase C87A/C104A
2LT5 2012-05-14T00:00:00+0000 0 Zymogen-FLG of the onconase
3FD7 2008-11-25T00:00:00+0000 1.53 Crystal structure of Onconase C87A/C104A-ONC

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Protein P-30 P22069 RNP30_LITPI