title: Structural basis of the interspecies interaction between the chaperone DnaK(Hsp70) and the co-chaperone GrpE of archaea and bacteria.
abstract: Hsp70s are chaperone proteins that are conserved in evolution and present in all prokaryotic and eukaryotic organisms. In the archaea, which form a distinct kingdom, the Hsp70 chaperones have been found in some species only, including Methanosarcina mazei. Both the bacterial and archaeal Hsp70(DnaK) chaperones cooperate with a GrpE co-chaperone which stimulates the ATPase activity of the DnaK protein. It is currently believed that the archaeal Hsp70 system was obtained by the lateral transfer of chaperone genes from bacteria. Our previous finding that the DnaK and GrpE proteins of M. mazei can functionally cooperate with the Escherichia coli GrpE and DnaK supported this hypothesis. However, the cooperation was surprising, considering the very low identity of the GrpE proteins (26%) and the relatively low identity of the DnaK proteins (56%). The aim of this work was to investigate the molecular basis of the observed interspecies chaperone interaction. Infrared resolution-enhanced spectra of the M. mazei and E. coli DnaK proteins were almost identical, indicating high similarity of their secondary structures, however, some small differences in band position and in the intensity of amide I' band components were observed and discussed. Profiles of thermal denaturation of both proteins were similar, although they indicated a higher thermostability of the M. mazei DnaK compared to the E. coli DnaK. Electrophoresis under non-denaturing conditions demonstrated that purified DnaK and GrpE of E. coli and M. mazei formed mixed complexes. Protein modeling revealed high similarity of the 3-dimensional structures of the archaeal and bacterial DnaK and GrpE proteins.
authors.affiliation: Department of Biochemistry, University of Gdansk, Gdańsk, Poland.
authors.forename: Michał A
authors.initials: MA
authors.lastname: Zmijewski
authors.forename: Joanna
authors.initials: J
authors.lastname: Skórko-Glonek
authors.forename: Fabio
authors.initials: F
authors.lastname: Tanfani
authors.forename: Bogdan
authors.initials: B
authors.lastname: Banecki
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kotlarz
authors.forename: Alberto J L
authors.initials: AJ
authors.lastname: Macario
authors.forename: Barbara
authors.initials: B
authors.lastname: Lipińska
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism*; D017020:Methanosarcina / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D046912:Multiprotein Complexes; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013045:Species Specificity; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D019843:Archaeal Proteins; D029968:Escherichia coli Proteins; C489400:GrpE protein, E coli; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D046912:Multiprotein Complexes; C063842:dnaK protein, E coli