| Autor: |
CORRE, F., JAXEL, C., FUENTES, J., MENGUY, T., FALSON, P., LEVINE, B. A., MØLLER, J. V., MAIRE, M. |
| Zdroj: |
Annals of the New York Academy of Sciences; April 2003, Vol. 986 Issue: 1 p90-95, 6p |
| Abstrakt: |
We have found that despite a markedly low calcium affinity the D813AD818A mutant is capable, after complexation with Cr.ATP, of occluding Ca2to the same extent (1-2 Ca2per ATPase monomer) as wild- type ATPase. The inherent ability of the synthetic L6-7 loop peptide to bind Ca2was demonstrated with murexide and mass spectrometry. NMR analysis indicated the formation of specific 1:1 cation complexes of the peptide with calcium and lanthanum with coordination by all three aspartate residues D813D815D818 that resulted in an altered conformation of the peptide chain. Overall our observations suggest that, in addition to mediating contact between the intramembranous Ca2binding sites and the cytosolic phosphorylation site as previously suggested, the L6-7 loop, in a preceding step, participates in the formation of an entrance port important for lodging Ca2at a high-affinity binding site inside the membrane. |
| Databáze: |
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