| Autor: |
Klemens MR; Department of Chemistry, University of Virginia, Charlottesville 22901., Grisham CM |
| Jazyk: |
angličtina |
| Zdroj: |
FEBS letters [FEBS Lett] 1988 Sep 12; Vol. 237 (1-2), pp. 4-8. |
| DOI: |
10.1016/0014-5793(88)80160-1 |
| Abstrakt: |
Water proton nuclear relaxation measurements are used to detect and characterize four distinct intermediate states for Gd3+ bound to Ca2+ sites of sarcoplasmic reticulum Ca2+-ATPase in complexes with ATP analogues. In the absence of nucleotides, Gd3+ binds to two occluded Ca2+ transport sites on Ca2+-ATPase which have a low accessibility to solvent water. In the presence of the nonhydrolyzable ATP analogue, Co(NH3)4AMPPCP, a new state for bound Gd3+ (still occluded and with fewer waters of hydration) is observed. In the presence of Co(NH3)4ATP or ATP, two additional states for bound Gd3+ are detected in the NMR studies. The first of these probably represents an intermediate state for bound Gd3+ during ATP hydrolysis. The latter is the most occluded Gd3+ site yet observed in these studies and is probably analogous to the highly occluded E1-P state observed with CrATP [(1987) Biochim. Biophys. Acta 898, 313-322]. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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