Evidence for involvement of the C-terminal domain in the dimerization of the CopY repressor protein from Enterococcus hirae

Abstract

Metal binding to the C-terminal region of the copper-responsive repressor protein CopY is responsible for homodimerization and the regulation of the copper homeostasis pathway in Enterococcus hirae. Specific involvement of the 38 C-terminal residues of CopY in dimerization is indicated by zonal and frontal (large zone) size exclusion chromatography studies. The studies demonstrate that the attachment of these CopY residues to the immunoglobulin binding domain of Streptococcal protein G (GB1) promotes dimerization of the monomeric protein. Although sensitivity of dimerization to removal of metal from the fusion protein is smaller than that found for CopY (as measured by ultracentrifugation studies), the demonstration that an unrelated protein (GB1) can be induced to dimerize by extending its sequence with the C-terminal portion of CopY confirms the involvement of this region in CopY homodimerization.

Metallochaperones and metalloregulation in bacteria

“…The DNA-binding domain adopts a canonical winged-helical domain like that found in ArsR, MerR and MarRs, as determined by the solution structure of the N-terminal domain of L. lactis CopR [130]. The C-terminal domain functions as the regulatory and dimerization domain [131] and is of unknown structure and responsible for the coordination of Cu I (Figure 4). CopYs regulate copper efflux and the oxidative stress response in a small number of bacterial pathogens from closely related Firmicutes, derived from the Lactococcus, Streptococcus and Enterococcus spp.…”

Metal-dependent allosteric activation and inhibition on the same molecular scaffold: the copper sensor CopY from Streptococcus pneumoniae

“…1A ). 18 The C-terminal regulatory domain functions as the dimerization domain, 19 is of unknown structure, and is thought to coordinate both Zn( ii ) and Cu( i ).…”

Purification Systems Based on Bacterial Surface Proteins

“…A few diverse examples of fusions to C-domains are exemplified here to illustrate some additional applications. The C1-domain has been used to increase the expression levels and aid in refolding of small recombinant proteins or peptides (Cheng & Patel 2004;Nadaud et al 2010;Pazehoski et al 2011). A repeat of the C3-domain has in another study been combined with luciferase to form a fusion protein with ability to www.intechopen.com detect antibodies bound to bacteria through a light-emitting reaction (Nakamura, M. et al 2011).…”