Sandbox Naama
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== The Eukaryotic Chaperonin TRiC/CCT == | == The Eukaryotic Chaperonin TRiC/CCT == | ||
<StructureSection load='3iyg' size='350' side='right' caption='Structure of HMG-CoA reductase (PDB entry [[3iyg]])' scene='Sandbox_Naama/Colored_tric/1'> | <StructureSection load='3iyg' size='350' side='right' caption='Structure of HMG-CoA reductase (PDB entry [[3iyg]])' scene='Sandbox_Naama/Colored_tric/1'> | ||
| - | The TRiC/CCT | + | The TRiC/CCT [http://proteopedia/wiki/index.php/Chaperonin chaperonin] aids to relatively 10% of the cellular proteome folding to their correct structure. |
The uniqe structure of the mamalian chaperonine TRic/CCT was first published in 2010 by Cong Y et al<ref>pmid:020194787</ref>. it was determined in a low resolution of 4.7 A by cryo-EM. It is composed of <scene name='Sandbox_Naama/Tric_dimer/1'> two identical heterooligomer </scene> ring shaped subunits consisting of eight different paralogous subunits <scene name='Sandbox_Naama/One_subunit/2'>view one subunit</scene> /<scene name='Sandbox_Naama/Colored_tric/1'>view full protein</scene> | The uniqe structure of the mamalian chaperonine TRic/CCT was first published in 2010 by Cong Y et al<ref>pmid:020194787</ref>. it was determined in a low resolution of 4.7 A by cryo-EM. It is composed of <scene name='Sandbox_Naama/Tric_dimer/1'> two identical heterooligomer </scene> ring shaped subunits consisting of eight different paralogous subunits <scene name='Sandbox_Naama/One_subunit/2'>view one subunit</scene> /<scene name='Sandbox_Naama/Colored_tric/1'>view full protein</scene> | ||
| - | Cong et al discovered that this chaperonine functions | ||
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| - | <scene name='Sandbox_Naama/Tric_dimer/1'>TRic dimer</scene> | ||
| - | The essential double-ring eukaryotic chaperonin TRiC/CCT (TCP1-ring complex or chaperonin containing TCP1) assists the folding of approximately 5-10% of the cellular proteome. Many TRiC substrates cannot be folded by other chaperonins from prokaryotes or archaea. These unique folding properties are likely linked to TRiC's unique heterooligomeric subunit organization, whereby each ring consists of eight different paralogous subunits in an arrangement that remains uncertain. Using single particle cryo-EM without imposing symmetry, we determined the mammalian TRiC structure at 4.7-A resolution. This revealed the existence of a 2-fold axis between its two rings resulting in two homotypic subunit interactions across the rings. A subsequent 2-fold symmetrized map yielded a 4.0-A resolution structure that evinces the densities of a large fraction of side chains, loops, and insertions. These features permitted unambiguous identification of all eight individual subunits, despite their sequence similarity. Independent biochemical near-neighbor analysis supports our cryo-EM derived TRiC subunit arrangement. We obtained a Calpha backbone model for each subunit from an initial homology model refined against the cryo-EM density. A subsequently optimized atomic model for a subunit showed approximately 95% of the main chain dihedral angles in the allowable regions of the Ramachandran plot. The determination of the TRiC subunit arrangement opens the way to understand its unique function and mechanism. In particular, an unevenly distributed positively charged wall lining the closed folding chamber of TRiC differs strikingly from that of prokaryotic and archaeal chaperonins. These interior surface chemical properties likely play an important role in TRiC's cellular substrate specificity. | ||
| - | As described before | ||
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| - | <scene name='Sandbox_Naama/Colored_tric/1'>Click here to see TRic colored by chains</scene> | ||
Current revision
The Eukaryotic Chaperonin TRiC/CCT
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- ↑ Cong Y, Baker ML, Jakana J, Woolford D, Miller EJ, Reissmann S, Kumar RN, Redding-Johanson AM, Batth TS, Mukhopadhyay A, Ludtke SJ, Frydman J, Chiu W. 4.0-A resolution cryo-EM structure of the mammalian chaperonin TRiC/CCT reveals its unique subunit arrangement. Proc Natl Acad Sci U S A. 2010 Mar 1. PMID:20194787
