scholarly journals Measuring protein stability in the GroEL chaperonin cage reveals massive destabilization

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Ilia Korobko ◽  
Hisham Mazal ◽  
Gilad Haran ◽  
Amnon Horovitz
Keyword(s):  
Protein Folding ◽  
Protein Stability ◽  
Mechanism Of Action ◽  
Bulk Solution ◽  
Electrostatic Effects ◽  
Protein Substrate ◽  
Chaperonin Groel ◽  
Substrate Stability

The thermodynamics of protein folding in bulk solution have been thoroughly investigated for decades. By contrast, measurements of protein substrate stability inside the GroEL/ES chaperonin cage have not been reported. Such measurements require stable encapsulation, that is no escape of the substrate into bulk solution during experiments, and a way to perturb protein stability without affecting the chaperonin system itself. Here, by establishing such conditions, we show that protein stability in the chaperonin cage is reduced dramatically by more than 5 kcal mol−1 compared to that in bulk solution. Given that steric confinement alone is stabilizing, our results indicate that hydrophobic and/or electrostatic effects in the cavity are strongly destabilizing. Our findings are consistent with the iterative annealing mechanism of action proposed for the chaperonin GroEL.

Electrostatic effects on protein stability

1992 ◽  
Vol 2 (1) ◽  
pp. 40-45 ◽  
Author(s):  
An-Suei Yang ◽  
Barry Honig
Keyword(s):  
Protein Stability ◽  
Electrostatic Effects

Protein folding in the cell: functions of two families of molecular chaperone, hsp 60 and TF55-TCP1

1993 ◽  
Vol 339 (1289) ◽  
pp. 313-326 ◽  
Keyword(s):  
Protein Folding ◽  
Mechanism Of Action ◽  
Molecular Chaperone ◽  
Polypeptide Chain ◽  
Family Members ◽  
Chain Folding ◽  
Cell Functions ◽  
Cellular Compartments

Two families of molecular chaperone, the hsp 60-GroEL family and the TF55-TCP1 family, have been discovered in evolutionarily related cellular compartments. A member of one of these families, hsp 60, has been shown to play a global role in polypeptide chain folding in mitochondria. We review here studies of both hsp 60 and other family members, discussing their essential physiological roles and mechanism of action.

scholarly journals Differential strengths of molecular determinants guide environment specific mutational fates

2017 ◽  
Author(s):  
Rohan Dandage ◽  
Rajesh Pandey ◽  
Gopal Jayaraj ◽  
Kausik Chakraborty
Keyword(s):  
Protein Folding ◽  
Molecular Evolution ◽  
Protein Stability ◽  
Environmental Effects ◽  
Environmental Conditions ◽  
Fitness Landscape ◽  
Dependent Manner ◽  
The Common ◽  
Physical And Chemical ◽  
Substrate Binding Protein

AbstractUnder the influence of selection pressures imposed by natural environments, organisms maintain competitive fitness through underlying molecular evolution of individual genes across the genome. For molecular evolution, how multiple interdependent molecular constraints play a role in determination of fitness under different environmental conditions is largely unknown. Here, using Deep Mutational Scanning (DMS), we quantitated empirical fitness of ∼2000 single site mutants of Gentamicin-resistant gene (GmR). This enabled a systematic investigation of effects of different physical and chemical environments on the fitness landscape of the gene. Molecular constraints of the fitness landscapes seem to bear differential strengths in an environment dependent manner. Among them, conformity of the identified directionalities of the environmental selection pressures with known effects of the environments on protein folding proves that along with substrate binding, protein stability is the common strong constraint of the fitness landscape. Our study thus provides mechanistic insights into the molecular constraints that allow accessibility of mutational fates in environment dependent manner.Author SummaryEnvironmental conditions play a central role in both organismal adaptations and underlying molecular evolution. Understanding of environmental effects on evolution of genotype is still lacking a depth of mechanistic insights needed to assist much needed ability to forecast mutational fates. Here, we address this issue by culminating high throughput mutational scanning using deep sequencing. This approach allowed comprehensive mechanistic investigation of environmental effects on molecular evolution. We monitored effects of various physical and chemical environments onto single site mutants of model antibiotic resistant gene. Alongside, to get mechanistic understanding, we identified multiple molecular constraints which contribute to various degrees in determining the resulting survivabilities of mutants. Across all tested environments, we find that along with substrate binding, protein stability stands out as the common strong constraints. Remarkable direct dependence of the environmental fitness effects on the type of environmental alteration of protein folding further proves that protein stability is the major constraint of the gene. So, our findings reveal that under the influence of environmental conditions, mutational fates are channeled by various degrees of strengths of underlying molecular constraints.

Electrostatic effects on protein stability

1992 ◽  
Vol 2 (2) ◽  
pp. 82
Author(s):  
An-Suei Yang ◽  
Barry Honig
Keyword(s):  
Protein Stability ◽  
Electrostatic Effects

Insights into chaperonin function from studies on archaeal thermosomes

2011 ◽  
Vol 39 (1) ◽  
pp. 94-98 ◽  
Author(s):  
Peter Lund
Keyword(s):  
Cell Death ◽  
Protein Folding ◽  
Recent Work ◽  
Mechanism Of Action ◽  
Molecular Chaperones ◽  
Short Review ◽  
Living Cells ◽  
Living Organisms ◽  
Opening And Closing ◽  
Hydrolysis Of

It is now well understood that, although proteins fold spontaneously (in a thermodynamic sense), many nevertheless require the assistance of helpers called molecular chaperones to reach their correct and active folded state in living cells. This is because the pathways of protein folding are full of traps for the unwary: the forces that drive proteins into their folded states can also drive them into insoluble aggregates, and, particularly when cells are stressed, this can lead, without prevention or correction, to cell death. The chaperonins are a family of molecular chaperones, practically ubiquitous in all living organisms, which possess a remarkable structure and mechanism of action. They act as nanoboxes in which proteins can fold, isolated from their environment and from other partners with which they might, with potentially deleterious consequences, interact. The opening and closing of these boxes is timed by the binding and hydrolysis of ATP. The chaperonins which are found in bacteria are extremely well characterized, and, although those found in archaea (also known as thermosomes) and eukaryotes have received less attention, our understanding of these proteins is constantly improving. This short review will summarize what we know about chaperonin function in the cell from studies on the archaeal chaperonins, and show how recent work is improving our understanding of this essential class of molecular chaperones.

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