What are Chaperones?

About Chaperones: 

• Chaperones are a group of proteins that have functional similarity and assist in protein folding.
• They are proteins that have the ability to prevent non-specific aggregation by binding to non-native proteins.
• After the new protein chain has been shaped correctly, chaperones move on. Or else the new chain is eliminated.
• Without chaperones, newly synthesised proteins would soon become a tangled mess of insoluble aggregates, hindering cellular processes.
• Chaperones are needed under physiological conditions too, for normal cellular function.
• There are several families of chaperones and each possesses different functions. Example of chaperon proteins are the “heat shock proteins” (Hsps).
• Major chaperones in humans include HSP70, HSC70 and HSP90: the numbers express the size of the proteins in kilodaltons.
  • In normal cells 1%–2% of all proteins present are heat shock proteins. This number rises threefold during stressful conditions.
• Misfolding of proteins can cause a number of diseases namely:
  • Parkinson’s disease: In which Alpha-synuclein protein, present in neurons, is wrongly folded.
  • Alzheimer: Brains of Alzheimer’s patients have plaques formed from aggregates of amyloid beta-peptide. This accumulation of amyloid fibrils is toxic, leading to widespread destruction of neurons – a ‘neurodegenerative’ disorder.
  • Autosomal dominant congenital cataract: In the eye lens, an abundant subset of proteins called alpha-crystallins themselves serve as chaperones – a single R116G mutation in human alpha crystallin is responsible for this.

Q1:What are Proteins?

These are large, complex molecules that are fundamental to the structure and functioning of all living organisms. They are composed of chains of smaller units called amino acids, which are linked together in specific sequences. Proteins serve a wide variety of critical roles inbiological systems.

Source: Single-molecule techniques reveal new dynamics of protein folding associated with Alzheimer’s disease progression

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