2eu1
Crystal structure of the chaperonin GroEL-E461K
Structural highlights
FunctionCH60_ECOLI Prevents misfolding and promotes the refolding and proper assembly of unfolded polypeptides generated under stress conditions.[HAMAP-Rule:MF_00600] Essential for the growth of the bacteria and the assembly of several bacteriophages. Also plays a role in coupling between replication of the F plasmid and cell division of the cell.[HAMAP-Rule:MF_00600] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe chaperonin GroEL adopts a double-ring structure with various modes of allosteric communication. The simultaneous positive intra-ring and negative inter-ring co-operativities alternate the functionality of the folding cavities in both protein rings. Negative inter-ring co-operativity is maintained through different inter-ring interactions, including a salt bridge involving Glu 461. Replacement of this residue by Lys modifies the temperature sensitivity of the substrate-folding activity of this protein, most likely as a result of the loss of inter-ring co-operativity. The crystal structure of the mutant chaperonin GroELE461K has been determined at 3.3A and compared with other structures: the wild-type GroEL, an allosteric defective GroEL double mutant and the GroEL-GroES-(ADP)7 complex. The inter-ring region of the mutant exhibits the following characteristics: (i) no salt-bridge stabilizes the inter-ring interface; (ii) the mutated residue plays a central role in defining the relative ring rotation (of about 22 degrees) around the 7-fold axis; (iii) an increase in the inter-ring distance and solvent accessibility of the inter-ring interface; and (iv) a 2-fold reduction in the stabilization energy of the inter-ring interface, due to the modification of inter-ring interactions. These characteristics explain how the thermal sensitivity of the protein's fundamental properties permits GroEL to distinguish physiological (37 degrees C) from stress (42 degrees C) temperatures. Crystal structure of the temperature-sensitive and allosteric-defective chaperonin GroELE461K.,Cabo-Bilbao A, Spinelli S, Sot B, Agirre J, Mechaly AE, Muga A, Guerin DM J Struct Biol. 2006 Sep;155(3):482-92. Epub 2006 Jul 8. PMID:16904907[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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