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what are chaperonins

What are Chaperonins? . Large double-ring-shaped protein complexes whose role in vivo is to assist protein folding. Where can chaperonins be found? . Classified by Sequence Homology Group I

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what are chaperonins

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    1. GroEL-GroES Chaperonin ComplexPDB ID = 1AON

    3. Where can chaperonins be found? Classified by Sequence Homology Group I     (GroES dependent) GroEL        eubacteria Hsp60        mitochondria     Rubisco      chloroplasts Group II    (GroES independent) thermosome/TF55     archaea TCP1/CCT               eukaryotic

    4. Causes of Aggregations Hydrophobic Interactions Interchain hydrogen bonding Intracellular Crowding U = Unfolded protein chain N = Native fold protein I = partially folded Intermediate

    5. Consequences of Aggregation Amyloid results from Structured fibrillar aggregates Associated Diseases    Alzheimer's    Huntington's

    6. Chaperonins counteract non-native protein aggregation During de novo folding Under Stress (e.g. high temperature)

    7. Experimental Details Method X-Ray Diffraction Resolution 3A R-Factor 24.8% Crystal Unit Cell Dimensions dim [Å]: a 255.26 b 265.25 c 184.40 angles [°]: alpha90.00 beta 90.00 gamma 90.00 Space Group P21212

    8. GroEL-GroES ArchitectureE = E. coli GroES S = Small One heptameric ring 7 identical 10kD subunits Chains O-U GroELL = Large Two heptameric rings stacked back to back 14 identical 57kD subunits Chains A-N

    9. GroEL-GroES Architecture

    10. GroES-GroEL Dimensions

    11. GroEL-GroES Sequences8337 Residues 58884 Atoms

    15. GroES Domain CATH Mainly Beta Roll

    16. GroEL Domains CATH Equatorial Mainly Alpha Orthogonal Bundle Intermediate Alpha Beta 2-Layer Sandwich Apical 3-Layer(bba) Sandwich

    21. GroES Mobile Loop

    22. GroEL Domains

    23. GroEL-GroES Binding Sites

    24. Conformational Change

    25. Conformational Change

    26. Conformational Change of Cavity

    27. Conformational Change

    28. How do chaperonins work? Bind non-native polypeptide through hydrophobic interaction Allow non-native polypeptide to fold in an isolated hydrophobic environment

    29. Overall Chaperonins Protein Folding Reaction 1. Non-native polypeptide bind to trans ring of GroEL2. 7ATP (equatorial) and GroES bind cis ring of GroEL2. Dissociation of 7ADP and GroES from from cis ring of GroEL3. Apical domain of GroEL undergo massive rotation and upward movement enlarging the cavity by 2X and shifting its surface properties from hydropobic to hydrophilic

    30. E. Coli have 4300 proteins 13% are ~55kD (500 residues) 10% polypeptides transit GroEL-GroES complex ~3uM cytosolic concentration of GroEL ~30uM ribosomes ½ life of 20-60 kD folded proteins 15sec to few mins

    32. Structural Neighbors Criteria used: 1AON chain A Z-Score>4.0 RMSD<4.0Å Length Difference<30.0% Gaps<30.0% Sequence identity<30.0% Found & used: 1BPW:A Z-Score 4.2 RMSD(Å) 3.8 Seq.(%) 2.3 Aligned / Size 88 / 503 Gap 25 Exp X-Ray

    34. ALDEHYDE DEHYDROGENASE(CHAIN A) PDB ID: 1BPW

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