Prokaryotic calcium‐binding protein of the calmodulin superfamily Calcium binding to a Saccharopolyspora erythraea 20 kDa protein

Abstract

The EF-hand calcium.binding protein from Saccharopoly~pora erythraea has been shown, using ~3Cd NMR, to possess three Cda*-ion binding sites. This indicates that of the four EF-hand motifs in the molecule, one (probably site 2) is unable to bind Cd2"-ions. Data from the titration of the protein with Ca:', in the presence of Quin2, were fitted to a curve calculated on the assumption that the protein contains three high affinity Ca 2" binding sites, two of which (PKt = $.0, pKa = 9.0) are strongly cooperative, and one single site (pK~ = 7.5). Preliminary ~H NMR experiments indicate marked structural changes upon Caa*-bindins.

Proteome Analysis of B. subtilis in Response to Calcium

“…Bacterial cell-pellets were resuspended in lysis buffer containing 7 M urea, 20 mM DTT, 1mM 127 CaCl 2 and protein inhibitor cocktail (Sigma-Aldrich, St. Louis MO.). Cell suspensions were lysed by sonication, according to the methods of Herbert et al [31]. After sonication the cell lysate was centrifuged at 20,000 xg for 10 min at 4°C.…”

“…However, none of the proteins or corresponding genes has been fully characterized. While the genes of some CaBP's have been cloned and partial characterization has been done, the functional activity remains to be investigated [30][31][32].…”

Structural basis for prokaryotic calciummediated regulation by a Streptomyces coelicolor calcium binding protein

“…The low sequence similarity (less than 28%) between CabD and other prokaryotic EF-hand proteins (Swan et al, 1987;Bylsma et al, 1992;Xi et al, 2000;Yang, 2001;Yonekawa et al, 2001;Michiels et al, 2002;Tossavainen et al, 2003), suggests that it has a distinctive and significant functions in physiologic processes in bacteria.…”

Crystallization and preliminary X-ray diffraction studies of the calcium-binding protein CalD fromStreptomyces coelicolor

“…The preliminary X-ray diffraction analysis of an 18 kDa calcium-binding protein from S. coelicolor A3(2) named CalD (SCO4411) offers a fundamental structural basis for understanding the possible regulatory roles of Ca 2+ in prokaryotes. The low sequence similarity (less than 28%) between CalD and other prokaryotic EF-hand proteins (Bylsma et al, 1992;Michiels et al, 2002;Swan et al, 1987;Tossavainen et al, 2003;Yonekawa et al, 2001) suggests that it has a potentially distinct and significant function in physiological processes. Here, we report the expression, purification and crystallization of CalD.…”