Prokaryotic calcium-binding protein of the calmodulin superfamily. Calcium binding to a Saccharopolyspora erythraea 20 kDa protein.
The EF-hand calcium-binding protein from Saccharopolyspora erythraea has been shown, using 113Cd NMR, to possess three Cd(2+)-ion binding sites. This indicates that of the four EF-hand motifs in the molecule, one (probably site 2) is unable to bind Cd(2+)-ions. Data from the titration of the protein with Ca2+, in the presence of Quin2, were fitted to a curve calculated on the assumption that the protein contains three high affinity Ca2+ binding sites, two of which (pK1 = 8.0, pK2 = 9.0) are strongly cooperative, and one single site (pK3 = 7.5). Preliminary 1H NMR experiments indicate marked structural changes upon Ca(2+)-binding.
Bylsma
N
N
Physical Chemistry 2, University of Lund, Sweden.
Drakenberg
T
T
Andersson
I
I
Leadlay
P F
PF
Forsén
S
S
D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D016930:Saccharopolyspora / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D005656:Fungal Proteins; D002118:Calcium