TY - JOUR
T1 - Reconstitution of ATP-dependent calcium transport from streptococci
AU - Ambudkar, S. V.
AU - Lynn, A. R.
AU - Maloney, P. C.
AU - Rosen, B. P.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1986
Y1 - 1986
N2 - Membrane vesicles of three streptococcal strains (Streptococcus faecalis, Streptococcus lactis, and Streptococcus sanguis) were extracted with octyl-β-D-glucoside in the presence of Escherichia coli lipid and glycerol. For reconstitution, the detergent extract was mixed with bath-sonicated E. coli lipid, in the presence of octyl-β-D-glucoside, and proteoliposomes were formed by a 25-fold dilution. ATP-dependent calcium accumulation by proteoliposomes was comparable to that found in parent vesicles. Recovery of this calcium transport activity was dependent on the inclusion of an osmolyte protein stabilant (glycerol, etc.) during solubilization. The properties of ATP-driven calcium transport were studied in the reconstituted system. In proteoliposomes, ATP-linked calcium accumulation was not affected by the protonophore, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, or by the ionophores, valinomycin and nigericin, in the presence of potassium, or by N,N'-dicyclohexylcarbodiimide, an inhibitor of the F0F1-ATPase. On the other hand, calcium transport was completely blocked by micromolar levels of orthovanadate; half-maximal inhibitions were observed at 0.4, 4, and 4 μM vanadate, for S. faecalis, S. lactis, and S. sanguis, respectively. This marked sensitivity to orthovanadate suggests operation of an E1-E2-type ion-motive pump. These data demonstrate that, in a reconstituted system, calcium transport is not linked to an ATP-dependent proton circulation via the F0-F1-ATPase, but rather is driven by a calcium-translocating ATPase. Thus, calcium extrusion from the cytosol of enteric, lactic acid, or oral streptococci is mediated by an ATP-linked process analogous to the ion-motive ATPases of eukaryotic membranes.
AB - Membrane vesicles of three streptococcal strains (Streptococcus faecalis, Streptococcus lactis, and Streptococcus sanguis) were extracted with octyl-β-D-glucoside in the presence of Escherichia coli lipid and glycerol. For reconstitution, the detergent extract was mixed with bath-sonicated E. coli lipid, in the presence of octyl-β-D-glucoside, and proteoliposomes were formed by a 25-fold dilution. ATP-dependent calcium accumulation by proteoliposomes was comparable to that found in parent vesicles. Recovery of this calcium transport activity was dependent on the inclusion of an osmolyte protein stabilant (glycerol, etc.) during solubilization. The properties of ATP-driven calcium transport were studied in the reconstituted system. In proteoliposomes, ATP-linked calcium accumulation was not affected by the protonophore, carbonyl cyanide p-trifluoromethoxyphenylhydrazone, or by the ionophores, valinomycin and nigericin, in the presence of potassium, or by N,N'-dicyclohexylcarbodiimide, an inhibitor of the F0F1-ATPase. On the other hand, calcium transport was completely blocked by micromolar levels of orthovanadate; half-maximal inhibitions were observed at 0.4, 4, and 4 μM vanadate, for S. faecalis, S. lactis, and S. sanguis, respectively. This marked sensitivity to orthovanadate suggests operation of an E1-E2-type ion-motive pump. These data demonstrate that, in a reconstituted system, calcium transport is not linked to an ATP-dependent proton circulation via the F0-F1-ATPase, but rather is driven by a calcium-translocating ATPase. Thus, calcium extrusion from the cytosol of enteric, lactic acid, or oral streptococci is mediated by an ATP-linked process analogous to the ion-motive ATPases of eukaryotic membranes.
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M3 - Article
C2 - 3096992
AN - SCOPUS:0022976052
SN - 0021-9258
VL - 261
SP - 15596
EP - 15600
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 33
ER -