The Library
Involvement of the cytoplasmic loop L6-7 in the entry mechanism for transport of Ca2+ through the sarcoplasmic reticulum Ca2+-ATPase
Tools
Tools
Tools
UNSPECIFIED. (2002) Involvement of the cytoplasmic loop L6-7 in the entry mechanism for transport of Ca2+ through the sarcoplasmic reticulum Ca2+-ATPase. JOURNAL OF BIOLOGICAL CHEMISTRY, 277 (15). pp. 13016-13028. ISSN 0021-9258
Full text not available from this repository.
Official URL: http://dx.doi.org/10.1074/jbc.M108899200
Abstract
We previously found that mutants of conserved aspartate residues of sarcoplasmic reticulum Ca2+-ATPase in the cytosolic loop, connecting transmembrane segments M6 and M7 (L6-7 loop), exhibit a strongly reduced sensitivity toward Ca2+ activation of the transport process. In this study, yeast membranes, expressing wild type and mutant Ca2+-ATPases, were reacted with Cr(.)ATP and tested for their ability to occlude 45 Ca2+ by HPLC analysis, after cation resin and Cl,E, treatment. We found that the D813A/D818A mutant that displays markedly low calcium affinity was capable of occluding Ca2+ to the same extent as wild type ATPase. Using NMR and mass spectrometry we have analyzed the conformational properties of the synthetic L6-7 loop and demonstrated the formation of specific 1:1 cation complexes of the peptide with calcium and lanthanum. All three aspartate Asp(813)/Asp(815)/Asp(818) were required to coordinate the trivalent lanthanide ion. Overall these observations suggest a dual function of the loop: in addition to mediating contact between the intramembranous Ca2+-binding sites and the cytosolic phosphorylation site (Zhang, Z., Lewis, D., Sumbilla, C., Inesi G., and Toyoshima, C. (2001) J. Biol. Chem. 276, 15232-15239), the L6-7 loop, in a preceding step, participates in the formation of an entrance port, before subsequent high affinity binding of Ca2+ inside the membrane.
| Item Type: | Journal Article |
|---|---|
| Subjects: | Q Science > QD Chemistry |
| Journal or Publication Title: | JOURNAL OF BIOLOGICAL CHEMISTRY |
| Publisher: | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC |
| ISSN: | 0021-9258 |
| Date: | 12 April 2002 |
| Volume: | 277 |
| Number: | 15 |
| Number of Pages: | 13 |
| Page Range: | pp. 13016-13028 |
| Identification Number: | 10.1074/jbc.M108899200 |
| Publication Status: | Published |
| URI: | http://wrap.warwick.ac.uk/id/eprint/11034 |
Data sourced from Thomson Reuters' Web of Knowledge
Actions (login required)
 |
View Item |
