Conformational changes in the foot protein of the sarcoplasmic reticulum assessed by site-directed fluorescent labeling

Biochemistry ◽  
1992 ◽  
Vol 31 (12) ◽  
pp. 3288-3293 ◽  
Author(s):  
J. J. Kang ◽  
A. Tarcsafalvi ◽  
A. D. Carlos ◽  
E. Fujimoto ◽  
Z. Shahrokh ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Conformational Changes ◽  
Fluorescent Labeling

Corrections - Conformational Changes in the Foot Protein of the Sarcoplasmic Reticulum Assessed by Site-Directed Fluorescent Labeling

Biochemistry ◽  
1992 ◽  
Vol 31 (20) ◽  
pp. 4922-4922
Author(s):  
J. Kang ◽  
A. Tarcsafalvi ◽  
A. Carlos ◽  
E. Fujimoto ◽  
Z. Shahrokh ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Conformational Changes ◽  
Fluorescent Labeling

scholarly journals Characterization of the sarcoplasmic reticulum proteins in the thermogenic muscles of fish.

1994 ◽  
Vol 127 (5) ◽  
pp. 1275-1287 ◽  
Author(s):  
B A Block ◽  
J O'Brien ◽  
G Meissner
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Direct Evidence ◽  
Striated Muscle ◽  
High Capacity ◽  
Muscle Cells ◽  
Immunoblot Analysis ◽  
Fluorescent Labeling ◽  
T Tubules ◽  
The Brain

Marlins, sailfish, spearfishes, and swordfish have extraocular muscles that are modified into thermogenic organs beneath the brain. The modified muscle cells, called heater cells, lack organized myofibrils and are densely packed with sarcoplasmic reticulum (SR), transverse (T) tubules, and mitochondria. Thermogenesis in the modified extraocular muscle fibers is hypothesized to be associated with increased energy turnover due to Ca2+ cycling at the SR. In this study, the proteins associated with sequestering and releasing Ca2+ from the SR (ryanodine receptor, Ca2+ ATPase, calsequestrin) of striated muscle cells were characterized in the heater SR using immunoblot and immunofluorescent techniques. Immunoblot analysis with a monoclonal antibody that recognizes both isoforms of nonmammalian RYRs indicates that the fish heater cells express only the alpha RYR isoform. The calcium dependency of [3H]ryanodine binding to the RYR isoform expressed in heater indicates functional identity with the non-mammalian alpha RYR isoform. Fluorescent labeling demonstrates that the RYR is localized in an anastomosing network throughout the heater cell cytoplasm. Measurements of oxalate supported 45Ca2+ uptake, Ca2+ ATPase activity, and [32P]phosphoenzyme formation demonstrate that the SR contains a high capacity for Ca2+ uptake via an ATP dependent enzyme. Immunoblot analysis of calsequestrin revealed a significant amount of the Ca2+ binding protein in the heater cell SR. The present study provides the first direct evidence that the heater SR system contains the proteins necessary for Ca2+ release, re-uptake and sequestration, thus supporting the hypothesis that thermogenesis in the modified muscle cells is achieved via an ATP-dependent cycling of Ca2+ between the SR and cytosolic compartments.

Electron Spin Resonance Studies on Conformational Changes of the Sarcoplasmic Reticulum Ca2+ – ATPase Induced by Synergistic Action of Calcium and ATP

1981 ◽  
Vol 36 (9) ◽  
pp. 1136-1143 ◽  
Author(s):  
Peter Laggner ◽  
Josef Suko ◽  
Christian Punzengruber ◽  
Rudolf Prager
Keyword(s):  
Electron Spin Resonance ◽  
Sarcoplasmic Reticulum ◽  
Electron Spin ◽  
Conformational Changes ◽  
Environmental Changes ◽  
Adenine Nucleotides ◽  
Membrane Vesicles ◽  
Heterocyclic Ring ◽  
Spin Labels ◽  
Spin Resonance

Abstract Changes in motional properties of the -SH group environment in sarcoplasmic reticulum ATPase [1] induced by addition of specific ligands to sarcoplasmic reticulum membrane vesicles were investigated systematically by electron spin resonance (e.p.r.) spectroscopy. Alternatively, two kinds of iodoacetamide analog spin labels, 4-(2-iodoacetamido)- 2,2,5,5-tetramethyl-1-pyrrolidinyl-N-oxyl (label I) and 4-(2-iodoacetamido)-2,2,6,6-tetramethyl- 1-piperidinyl-N-oxyl (label II) were used. The labeling conditions were chosen such that less than three moles of -SH groups per mole of ATPase reacted with the spin labels. A marked increase in isotropic motion of either spin label was observed on addition of calcium in millimolar concentrations plus ATP or β-γ-methylene ATP. Qualitatively similar but smaller changes were also observed with inosine 5'-triphosphate (ITP), acetylphosphate, or ADP in the presence of calcium. These effects were independent of added magnesium. The spectral changes induced by β-γ-methylene ATP, which binds to the ATPase but is not hydrolyzed, and those of calcium plus ADP suggest a conformational change due to simultaneous binding of these ligands in the absence of enzyme phosphorylation. These changes in e.p.r. spectra were different in quality and magnitude from those observed upon separate binding of calcium or adenine nucleotides. The two spin labels, differing only in their numbers of heterocyclic ring atoms, were found to reflect environmental changes in different ways. This demonstrates the usefulness of employing different spin labels to detect and interpret structural transitions in macromolecular assemblies.

scholarly journals Fast Kinetic Analysis of Conformational Changes in Mutants of the Ca2+-ATPase of Sarcoplasmic Reticulum

2000 ◽  
Vol 275 (8) ◽  
pp. 5400-5408 ◽  
Author(s):  
Thomas Lykke-Møller Sørensen ◽  
Yves Dupont ◽  
Bente Vilsen ◽  
Jens Peter Andersen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Kinetic Analysis ◽  
Conformational Changes ◽  
Fast Kinetic
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