GroEL, GroES

The GroEL-GroES complex binds and releases newly synthesized polypeptides in an ATP-dependent cycle... 

How does the GroEL-GroES complex function as a chaperone to assist protein folding Although several aspects of the mechanism are not clear, the main features of the functional cycle are known. The first step is the... 

Chen, S. et al. Eocation of a folding protein and shape changes in GroEL-GroES complexes imaged by cryo-electron microscopy. Nature 371 261-264, 1994. 

GroES closes off one end of the GroEL cylinder The GroEL-GroES complex binds and... 

The desulfinase enzyme from R. erythropolis IGTS8 and R. erythropolis KA2-5-1 have been isolated and characterized [55,126,163,164] however, the latter enzyme had to be cloned into E. coli, to obtain sufficient enzyme for characterization. Both enzymes have an optimum activity at a temperature of 35°C, but slightly different pH optimum (Table 7). The Km values for HBPSi for the two enzymes were similar but the kcat values were different, probably due to the use of different assays to assess enzyme activity. The fccat values for the IGTS8 enzyme did match closely with that reported by the Gray study [53], Expression of the KA2-5-1 enzyme in E. coli required co-expression of chaperonin genes, groEL/groES. 

Xu Z, Horwich AL, Sigler PB (1997) The crystal structure of the asymmetric GroEL-GroES-(ADP)7 chaperonin complex. Nature 388 741-750... 

Expanded GroEL-GroES complex with enclosed folding polypeptide0... 

Within the GroEL-GroES cage polypeptide chains can fold without becoming entangled with other proteins or being cleaved by protein-hydrolyzing enzymes... 

The reaction cycle starts with a GroEL-GroES complex containing ADP bound to the cis ring (Fig. 2, step 1). The... 

Figure 2 Mechanism of action of the GroEL/GroES system in E.coli. P, unfolded polypeptide chain. N, native folded chain. For details, see text. Reprinted from Reference (16), Copyright 2003 with permission from Elsevier.

Farr GW, Fenton WA, Rospert S, Horwich AR. Folding with and without encapsulation by cis and trans-only GroEL-GroES complexes. EMBO J 2001 22 3220-3230. 

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