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ATP-driven molecular chaperone machines.

Clare DK, Saibil HR - Biopolymers (2013)

Bottom Line: This review is focused on the mechanisms by which ATP binding and hydrolysis drive chaperone machines assisting protein folding and unfolding.A survey of the key, general chaperone systems Hsp70 and Hsp90, and the unfoldase Hsp100 is followed by a focus on the Hsp60 chaperonin machine which is understood in most detail.These structures suggest a mechanism by which GroEL can forcefully unfold and then encapsulate substrates for subsequent folding in isolation from all other binding surfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.

No MeSH data available.


Related in: MedlinePlus

Structures of GroEL complexes with non-native MDH and gp23. Cryo-EM maps and fits for GroEL–MDH (left-hand two columns) and GroEL–gp23 (right-hand two columns) shown from the top, side, and bottom (EM Databank ID for GroEL–gp23 complexes: EMD-1544 and EMD-1545). GroEL density is shown as a white transparent surface with the substrate density shown as cyan. Helices H and I are shown as red and orange with the rest of the coordinates shown in blue. Two structures of GroEL–MDH are shown, from an ensemble of five structures that were determined by classification of a heterogeneous data set. The same approach was used for the GroEL–gp23 complexes.
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fig07: Structures of GroEL complexes with non-native MDH and gp23. Cryo-EM maps and fits for GroEL–MDH (left-hand two columns) and GroEL–gp23 (right-hand two columns) shown from the top, side, and bottom (EM Databank ID for GroEL–gp23 complexes: EMD-1544 and EMD-1545). GroEL density is shown as a white transparent surface with the substrate density shown as cyan. Helices H and I are shown as red and orange with the rest of the coordinates shown in blue. Two structures of GroEL–MDH are shown, from an ensemble of five structures that were determined by classification of a heterogeneous data set. The same approach was used for the GroEL–gp23 complexes.

Mentions: Cryo-EM has also been used to probe the structure of non-native proteins bound to GroEL. Initial studies observed that the substrates were bound to helices H and I, with substrate density protruding from the GroEL ring.117,125,126 In a more detailed cryo-EM study, denatured MDH was shown to occupy multiple positions on GroEL. Most complexes showed substrate density at helix I and the underlying segment in 3–4 apical domains, but one had a bilobed appearance reminiscent of the folded form of MDH located closer to the entrance of the cavity114 (Figure 7, left 2 panels).


ATP-driven molecular chaperone machines.

Clare DK, Saibil HR - Biopolymers (2013)

Structures of GroEL complexes with non-native MDH and gp23. Cryo-EM maps and fits for GroEL–MDH (left-hand two columns) and GroEL–gp23 (right-hand two columns) shown from the top, side, and bottom (EM Databank ID for GroEL–gp23 complexes: EMD-1544 and EMD-1545). GroEL density is shown as a white transparent surface with the substrate density shown as cyan. Helices H and I are shown as red and orange with the rest of the coordinates shown in blue. Two structures of GroEL–MDH are shown, from an ensemble of five structures that were determined by classification of a heterogeneous data set. The same approach was used for the GroEL–gp23 complexes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814418&req=5

fig07: Structures of GroEL complexes with non-native MDH and gp23. Cryo-EM maps and fits for GroEL–MDH (left-hand two columns) and GroEL–gp23 (right-hand two columns) shown from the top, side, and bottom (EM Databank ID for GroEL–gp23 complexes: EMD-1544 and EMD-1545). GroEL density is shown as a white transparent surface with the substrate density shown as cyan. Helices H and I are shown as red and orange with the rest of the coordinates shown in blue. Two structures of GroEL–MDH are shown, from an ensemble of five structures that were determined by classification of a heterogeneous data set. The same approach was used for the GroEL–gp23 complexes.
Mentions: Cryo-EM has also been used to probe the structure of non-native proteins bound to GroEL. Initial studies observed that the substrates were bound to helices H and I, with substrate density protruding from the GroEL ring.117,125,126 In a more detailed cryo-EM study, denatured MDH was shown to occupy multiple positions on GroEL. Most complexes showed substrate density at helix I and the underlying segment in 3–4 apical domains, but one had a bilobed appearance reminiscent of the folded form of MDH located closer to the entrance of the cavity114 (Figure 7, left 2 panels).

Bottom Line: This review is focused on the mechanisms by which ATP binding and hydrolysis drive chaperone machines assisting protein folding and unfolding.A survey of the key, general chaperone systems Hsp70 and Hsp90, and the unfoldase Hsp100 is followed by a focus on the Hsp60 chaperonin machine which is understood in most detail.These structures suggest a mechanism by which GroEL can forcefully unfold and then encapsulate substrates for subsequent folding in isolation from all other binding surfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, Malet Street, London WC1E 7HX, UK.

No MeSH data available.


Related in: MedlinePlus