|
rdf:type |
|
|
lifeskim:mentions |
|
|
pubmed:issue |
2
|
|
pubmed:dateCreated |
1989-3-28
|
|
pubmed:abstractText |
Scallop sarcoplasmic reticulum (SR), visualized in situ by freeze-fracture and deep-etching, is characterized by long tubes displaying crystalline arrays of Ca2+-ATPase dimer ribbons, resembling those observed in isolated SR vesicles. The orderly arrangement of the Ca2+-ATPase molecules is well preserved in muscle bundles permeabilized with saponin. Treatment with saponin, however, is not needed to isolate SR vesicles displaying a crystalline surface structure. Omission of ATP from the isolation procedure of SR vesicles does not alter the dimeric organization of the Ca2+-ATPase, although the overall appearance of the tubes seems to be affected: the edges of the vesicles are scalloped and the individual Ca2+-ATPase molecules are not clearly defined. The effect of Ca2+ on isolated scallop SR vesicles was investigated by correlating the enzymatic activity and calcium-binding properties of the Ca2+-ATPase with the surface structure of the vesicles, as revealed by electron microscopy. The dimeric organization of the membrane is preserved at Ca2+ concentrations where the Ca2+ binds to the high affinity sites (half-maximum saturation at pCa approximately 7.0 with a Hill coefficient of 2.1) and the Ca2+-ATPase is activated (half-maximum activation at pCa approximately 6.8 with a Hill coefficient of 1.84). Higher Ca2+ concentrations disrupt the crystalline surface array of the SR tubes, both in the presence and absence of ATP. We discuss here whether the Ca2+-ATPase dimer identified as a structural unit of the SR membrane represents the Ca2+ pump in the membrane.
|
|
pubmed:grant |
|
|
pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-1259145,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-132972,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-13955687,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-202465,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2451665,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2581506,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2931117,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2931429,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2932170,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2932171,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2939255,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2952035,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2952650,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2959957,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2965700,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-2970823,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-3155517,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-3416,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-3778883,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-4057256,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-4274560,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-5571732,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6093108,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6148355,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6213963,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6222773,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6225781,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6225783,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6232390,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6232396,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6244305,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6251228,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6262373,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6296150,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6303204,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-6885910,
http://linkedlifedata.com/resource/pubmed/commentcorrection/2521860-7197728
|
|
pubmed:language |
eng
|
|
pubmed:journal |
|
|
pubmed:citationSubset |
IM
|
|
pubmed:chemical |
|
|
pubmed:status |
MEDLINE
|
|
pubmed:month |
Feb
|
|
pubmed:issn |
0021-9525
|
|
pubmed:author |
|
|
pubmed:issnType |
Print
|
|
pubmed:volume |
108
|
|
pubmed:owner |
NLM
|
|
pubmed:authorsComplete |
Y
|
|
pubmed:pagination |
511-20
|
|
pubmed:dateRevised |
2010-11-18
|
|
pubmed:meshHeading |
pubmed-meshheading:2521860-Adenosine Triphosphate,
pubmed-meshheading:2521860-Animals,
pubmed-meshheading:2521860-Calcium,
pubmed-meshheading:2521860-Calcium-Transporting ATPases,
pubmed-meshheading:2521860-Freeze Etching,
pubmed-meshheading:2521860-Freeze Fracturing,
pubmed-meshheading:2521860-Macromolecular Substances,
pubmed-meshheading:2521860-Microscopy, Electron,
pubmed-meshheading:2521860-Mollusca,
pubmed-meshheading:2521860-Muscles,
pubmed-meshheading:2521860-Sarcoplasmic Reticulum
|
|
pubmed:year |
1989
|
|
pubmed:articleTitle |
Effect of Ca2+ on the dimeric structure of scallop sarcoplasmic reticulum.
|
|
pubmed:affiliation |
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110.
|
|
pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, U.S. Gov't, Non-P.H.S.,
Research Support, Non-U.S. Gov't
|
