Large-scale structural changes in the sarcoplasmic reticulum ATPase appear essential for calcium transport.
Model refinement calculations utilizing the results from time-resolved x-ray diffraction studies indicate that specific, large-scale changes (i.e., structural changes over a large length scale or long range) occur throughout the cylindrically averaged profile structure of the sarcoplasmic reticulum ATPase upon its phosphorylation during calcium active transport. Several physical-chemical factors, all of which slow the kinetics of phosphoenzyme formation, induce specific, large-scale changes throughout the profile structure of the unphosphorylated enzyme that in general are opposite to those observed upon phosphorylation. These results suggest that such large-scale structural changes in the ATPase occurring upon its phosphorylation are required for its calcium transport function.
Blasie
J K
JK
Department of Chemistry, University of Pennsylvania, Philadelphia 19104.
Pascolini
D
D
Asturias
F
F
Herbette
L G
LG
Pierce
D
D
Scarpa
A
A
D001693:Biological Transport, Active; D002118:Calcium / Q000493:pharmacokinetics*; D000252:Calcium-Transporting ATPases / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D011487:Protein Conformation; D012519:Sarcoplasmic Reticulum / Q000201:enzymology / Q000648:ultrastructure*; D013329:Structure-Activity Relationship; D014961:X-Ray Diffraction
D000252:Calcium-Transporting ATPases; D002118:Calcium