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Title | An expanded conformation of single-ring GroEL-GroES complex encapsulates an 86 kDa substrate. |
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Journal, issue, pages | Structure, Vol. 14, Issue 11, Page 1711-1722, Year 2006 |
Publish date | Jan 16, 2007 |
Authors | Dong-Hua Chen / Jiu-Li Song / David T Chuang / Wah Chiu / Steven J Ludtke / |
PubMed Abstract | Electron cryomicroscopy reveals an unprecedented conformation of the single-ring mutant of GroEL (SR398) bound to GroES in the presence of Mg-ATP. This conformation exhibits a considerable expansion ...Electron cryomicroscopy reveals an unprecedented conformation of the single-ring mutant of GroEL (SR398) bound to GroES in the presence of Mg-ATP. This conformation exhibits a considerable expansion of the folding cavity, with approximately 80% more volume than the X-ray structure of the equivalent cis cavity in the GroEL-GroES-(ADP)(7) complex. This expanded conformation can encapsulate an 86 kDa heterodimeric (alphabeta) assembly intermediate of mitochondrial branched-chain alpha-ketoacid dehydrogenase, the largest substrate ever observed to be cis encapsulated. The SR398-GroES-Mg-ATP complex is found to exist as a mixture of standard and expanded conformations, regardless of the absence or presence of the substrate. However, the presence of even a small substrate causes a pronounced bias toward the expanded conformation. Encapsulation of the large assembly intermediate is supported by a series of electron cryomicroscopy studies as well as the protection of both alpha and beta subunits of the substrate from tryptic digestion. |
External links | Structure / PubMed:17098196 |
Methods | EM (single particle) |
Resolution | 20.0 Å |
Structure data | EMDB-1286: EMDB-1289: EMDB-1295: EMDB-1296: EMDB-1297: EMDB-1298: |
Source |
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