DnaK/DnaJ chaperone system reactivates endogenous E. coli thermostable FBP aldolase in vivo and in vitro; the effect is enhanced by GroE heat shock proteins
| Autor: | Sabina Kedzierska, Alina Taylor, Grzegorz Jezierski |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Protein Denaturation
Hot Temperature Fructose-bisphosphate aldolase In Vitro Techniques Cell Fractionation Biochemistry Heat shock protein Fructose-Bisphosphate Aldolase Chaperonin 10 Escherichia coli Denaturation (biochemistry) HSP70 Heat-Shock Proteins Heat-Shock Proteins biology Escherichia coli Proteins Aldolase A Cell Biology GroES Chaperonin 60 Original Articles HSP40 Heat-Shock Proteins GroEL Mutagenesis Chaperone (protein) biology.protein HSP60 Molecular Chaperones |
| Zdroj: | Cell stresschaperones. 6(1) |
| ISSN: | 1355-8145 |
| Popis: | Thermally aggregated, endogenous proteins in Escherichia coli cells form the S fraction, which is separable by sucrose density gradient centrifugation. To date, relatively little is known about the mechanisms of elimination of the heat-aggregated proteins from E. coli cells and the composition of the S fraction. We have identified several proteins of the S fraction using 2D-gel electrophoresis and microsequencing. A thermostable II class fructose-1,6-bisphosphate aldolase (Fda protein) appeared to be one of numerous proteins of the S fraction. Fda was purified from E. coli overproducer strain and used as a model substrate for investigation of the role of Hsps in prevention and repair of thermal denaturation of proteins both in vivo and in vitro. We found that the heat inactivation of Fda was reversible and that its reactivation in vivo and in vitro required mainly the assistance of the DnaK/DnaJ chaperone system. The dnaK756 and dnaJ259 mutations had a negative effect on the reactivation of thermally inactivated Fda. Moreover, we showed that the reactivation process in vitro was enhanced when GroEL/GroES were added together with DnaK/DnaJ. GroEL/GroES alone were inefficient in the resolubilization or reactivation of the heat-aggregated Fda. It is supposed that the denaturation of the thermostable Fda in vivo results rather from a temporary and transient deficit of Hsps than from the direct heat effect. |
| Databáze: | OpenAIRE |
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