Fig. 3: TRiC-tubulin-S3 structure showing a near-natively folded tubulin attached to the cis-ring of TRiC. | Communications Biology

Fig. 3: TRiC-tubulin-S3 structure showing a near-natively folded tubulin attached to the cis-ring of TRiC.

From: Pathway and mechanism of tubulin folding mediated by TRiC/CCT along its ATPase cycle revealed using cryo-EM

Fig. 3

a Enlarged views of the engaged tubulin within the TRiC chamber in the S3 state. The tubulin N/I/C domains were rendered in blue, yellow and red, respectively, with this color scheme followed throughout the figures. Red dotted circles indicate dynamic regions of the I ___domain of tubulin. b, c The resolved β-tubulin inside the cis-ring of TRiC-tubulin-S3 (b), and its high-resolution structural features (c). d Mapping of the detected cross-links made by tubulin K58 and K252 (cyan spheres) with the TRiC subunits in the cis-ring of TRiC-tubulin-S3. Note that every TRiC subunit made at least one such cross-link. e Ribbon diagram depictions of the association between each TRiC subunit and tubulin in S3, showing the close associations of the N/C domains of tubulin with CCT6 hemisphere subunits CCT1/3/6/8, and loose associations of the tubulin I ___domain with CCT2 hemisphere subunits CCT7/5/2/4. Cα atoms of the TRiC amino acid residues within 4 Å distance of tubulin were shown as cyan balls. f Magnified views of the regions indicated with red dotted frames in (g) to show the salt-bridge interactions formed between tubulin and CCT3/6/8. g XL-MS-analysis-derived sites on TRiC (blue spheres) cross-linked with tubulin and mapped onto the corresponding indicated TRiC structure. This analysis suggested a shift in the interaction locations induced by ATP-binding/hydrolysis.

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