Loosely packed papain prosegment displays inhibitory activity
| Autor: | Arturo Rojo-Domínguez, Luis H. Gutiérrez-González, Ruy Pérez-Montfort, Nallely E. Cabrera-González, A. Jaqueline Padilla-Zúñiga |
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| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Proteases Circular dichroism Protein Denaturation Protein Folding medicine.medical_treatment Biophysics Biochemistry Turn (biochemistry) chemistry.chemical_compound Papain medicine Genes Synthetic Animals Humans Enzyme Inhibitors Molecular Biology Protease Chemistry Circular Dichroism Hydrogen-Ion Concentration Molten globule Recombinant Proteins Protein Structure Tertiary Folding (chemistry) Crystallography Spectrometry Fluorescence Thermodynamics Cysteine |
| Zdroj: | Archives of biochemistry and biophysics. 446(2) |
| ISSN: | 0003-9861 |
| Popis: | Most protease prosegments are co-synthesized at the N-termini of cysteine proteases and are involved in folding assistance, inhibition, and activation of their mature enzymes. By using circular dichroism, UV-difference and fluorescence spectroscopies, we studied the thermal unfolding of papain prosegment. The transition seems to be two-state and reversible, with an unfolded state prone to aggregation. Unfolding thermodynamic parameters obtained show low values both for Δ H T m and Δ Cp U , indicative of a loosely packed three-dimensional conformation for the prosegment at near-neutral pH conditions. In spite of these results, fluorescence experiments demonstrate that papain prosegment is able to recognize and inhibit its cognate protease. An acid medium induces a molten globule-like state without intermediates, which in turn undergoes an irreversible thermal unfolding. Our results suggest that papain prosegment has a high degree of conformational flexibility, with the ability to form not only a molten globule-like structure in activating conditions, but also requiring an induced fit in order to be functional as inhibitor. |
| Databáze: | OpenAIRE |
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