Why in the News?
Walter Kauzmann’s 1959 idea that protein folding relies on water-loving and water-avoiding parts has now been challenged by new research showing protein cores are more flexible than once believed.
Protein and Protein Folding – Overview
- Proteins: Biological macromolecules made of 20 amino acids in specific sequences.
- Folding: Sequence dictates 3D shape, essential for function.
- Water Interaction:
- Hydrophilic (e.g., lysine) → outer surface.
- Hydrophobic (e.g., tryptophan) → buried in core.
- Kauzmann Hypothesis (1959): Proteins have a hydrophobic core and hydrophilic surface, guiding folding.
- 1960s X-ray Evidence: Confirmed hydrophobic residues inside, hydrophilic outside.
- Earlier Belief: Core was highly sensitive—small changes could destabilize protein.
Recent Research:
- Study Design: Tested 78,125 amino acid combos at 7 sites in cores of 3 proteins:
- Human SH3 domain (FYN tyrosine kinase)
- Barley CI-2A protein
- E. coli CspA protein
- Findings:
- Many changes harmful, but thousands stable (e.g., SH3-FYN had 12,000+ stable conformations).
- Machine learning accurately predicted stability even with <25% sequence similarity.
Implications:
- Protein Engineering: Core modifications may be possible without losing stability—beneficial for therapeutics.
- Evolutionary Insight: Protein cores may have been more adaptable during evolution than once thought.
| [UPSC 2010] Which one of the following processes in the bodies of living organisms is a digestive process?
(a) Breakdown of proteins into amino acids * (b) Breakdown of glucose into CO2 and H2O (c) Conversion of glucose into glycogen (d) Conversion of amino acids into proteins. |
