title: State of aggregation of the (Ca2+ + Mg2+)-ATPase studied using chemical cross-linking.
abstract: We have studied cross-linking of the (Ca2+ + Mg2+)-ATPase in sarcoplasmic reticulum and in reconstituted systems, using glutaraldehyde, cupric-1,10-phenanthroline and 3,3'-dithiobis (sulphosuccinimidylpropionate). All reagents produce extensive cross-linking, forming aggregates too large to enter polyacrylamide gels. Only traces of cross-linked dimeric ATPase species are formed. Saturation transfer electron spin resonance spectra of spin-labelled sarcoplasmic reticulum cross-linked with glutaraldehyde are also consistent with the formation of extensively cross-linked aggregates in the membrane. The results are interpreted in terms of dynamic clusters of ATPase molecules in the membrane, probably in the form of rows of ATPase molecules.
authors.affiliation: Department of Biochemistry, University of Southampton, UK.
authors.forename: R M
authors.initials: RM
authors.lastname: Napier
authors.forename: J M
authors.initials: JM
authors.lastname: East
authors.forename: A G
authors.initials: AG
authors.lastname: Lee
mesh_terms: D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D003432:Cross-Linking Reagents / Q000494:pharmacology*; D004578:Electron Spin Resonance Spectroscopy; D005976:Glutaral / Q000494:pharmacology; D007425:Intracellular Membranes / Q000201:enzymology; D046911:Macromolecular Substances; D009132:Muscles / Q000201:enzymology; D010618:Phenanthrolines / Q000494:pharmacology; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013388:Succinimides / Q000494:pharmacology
chemical_list: D003432:Cross-Linking Reagents; D046911:Macromolecular Substances; D010618:Phenanthrolines; D013388:Succinimides; C035759:3,3'-dithiobis(sulfosuccinimidyl propionate); D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D005976:Glutaral; C025205:1,10-phenanthroline