6533b7d3fe1ef96bd1260c7f

RESEARCH PRODUCT

Thermostability of Two Cyanobacterial GrpE Thermosensors

Dirk SchneiderSandra BarthelEva Rupprecht

subject

PhysiologyMolecular Sequence DataProtein domainPlant SciencePlasma protein bindingCyanobacteriaProtein structureBacterial ProteinsHeat shock proteinEscherichia coliAmino Acid SequencePeptide sequenceHeat-Shock ProteinsThermostabilitySequence Homology Amino AcidbiologyProtein StabilityChemistryCircular DichroismGenetic Complementation TestSynechocystisSynechocystisTemperatureCell BiologyGeneral Medicinebiology.organism_classificationProtein Structure TertiaryCross-Linking ReagentsChaperone (protein)Biophysicsbiology.proteinbacteriaProtein MultimerizationProtein Binding

description

GrpE proteins act as co-chaperones for DnaK heat-shock proteins. The dimeric protein unfolds under heat stress conditions, which results in impaired interaction with a DnaK protein. Since interaction of GrpE with DnaK is crucial for the DnaK chaperone activity, GrpE proteins act as a thermosensor in bacteria. Here we have analyzed the thermostability and function of two GrpE homologs of the mesophilic cyanobacterium Synechocystis sp. PCC 6803 and of the thermophilic cyanobacterium Thermosynechococcus elongatus BP1. While in Synechocystis an N-terminal helix pair of the GrpE dimer appears to be the thermosensing domain and mainly mediates GrpE dimerization, the C-terminal four-helix bundle is involved in additional stabilization of the dimeric structure. The four-helix bundle domain has a key role in the thermophilic cyanobacterium, since dimerization of the Thermosynechococcus protein appears to be mediated by the four-helix bundle domain, and melting of this domain is linked to monomerization of the GrpE protein. Thus, in two related cyanobacteria the GrpE thermosensing function might be mediated by different protein domains.

yearjournalcountryeditionlanguage
2011-08-24Plant and Cell Physiology
https://doi.org/10.1093/pcp/pcr116