ABCC8 p.Leu814Ala
| Predicted by SNAP2: | A: D (75%), C: D (63%), D: D (91%), E: D (85%), F: N (57%), G: D (85%), H: D (85%), I: D (66%), K: D (91%), M: N (72%), N: D (85%), P: D (91%), Q: D (80%), R: D (85%), S: D (80%), T: D (80%), V: D (63%), W: D (80%), Y: D (75%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: N, K: D, M: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Involvement of the cytoplasmic loop L6-7 in the en... J Biol Chem. 2002 Apr 12;277(15):13016-28. Epub 2002 Jan 18. Menguy T, Corre F, Juul B, Bouneau L, Lafitte D, Derrick PJ, Sharma PS, Falson P, Levine BA, Moller JV, le Maire M
Involvement of the cytoplasmic loop L6-7 in the entry mechanism for transport of Ca2+ through the sarcoplasmic reticulum Ca2+-ATPase.
J Biol Chem. 2002 Apr 12;277(15):13016-28. Epub 2002 Jan 18., [PMID:11801592]
Abstract [show]
We previously found that mutants of conserved aspartate residues of sarcoplasmic reticulum Ca(2+)-ATPase in the cytosolic loop, connecting transmembrane segments M6 and M7 (L6-7 loop), exhibit a strongly reduced sensitivity toward Ca(2+) activation of the transport process. In this study, yeast membranes, expressing wild type and mutant Ca(2+)-ATPases, were reacted with Cr small middle dotATP and tested for their ability to occlude (45)Ca(2+) by HPLC analysis, after cation resin and C(12)E(8) treatment. We found that the D813A/D818A mutant that displays markedly low calcium affinity was capable of occluding Ca(2+) 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 Ca(2+)-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 Ca(2+) inside the membrane.
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No. Sentence Comment
351 Similarly, Asahi et al. (27) report that the site-directed mutants L814A, I816A, or M817A have Ca2ϩ transport activity so low that no functional interaction with phospholamban could be evaluated.
X
ABCC8 p.Leu814Ala 11801592:351:67
status: NEW