Spectral studies on the calcium-binding properties of Mts1 protein and its interaction with target protein.
Two calcium-binding sites of the Mts1 protein, a member of S-100 protein family, were distinguished with the Fluo-3 fluorescent technique. The geometric mean of the apparent dissociation constant (Kd) for these two sites is 2.6 microM; the Hill coefficient (nH) is 0.98. In the presence of a novel target protein p37, isolated from the mouse adenocarcinoma cell line CSML-100, Mts1 binds Ca2+ ions with higher affinity and with strong positive cooperativity (Kd = 0.2 microM, nH = 1.91). Interaction of Mts1 with p37 is confirmed by the fluorescent probe 2-p-toluidinylnaphthalene-6-sulfonate (TNS). Reaction with TNS shows that p37 interacts with the hydrophobic site of Mts1 which is exposed due to the binding of Ca2+ ions.
Dukhanina
E A
EA
Engelhardt Institute of Molecular Biology, Russian Academy of Science, Moscow, Russian Federation. buh@genom-ii.eimb.rssi.ru
Dukhanin
A S
AS
Lomonosov
M Y
MY
Lukanidin
E M
EM
Georgiev
G P
GP
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; D013053:Spectrophotometry; D014407:Tumor Cells, Cultured
D002135:Calcium-Binding Proteins; D011506:Proteins; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C470944:S100a4 protein, mouse; D002118:Calcium