Synthesis and application of novel bifunctional spin labels.
The synthesis of new bifunctional spin-labeled cross-linking reagents is described. Covalent attachment to papain was achieved via a thiol-specific thiosulfonate residue and, for the second anchor point, via a nonspecific photoreactive azido function. The thiosulfonate formed a reversible disulfide linkage, which could be cleaved again reductively by dithiothreitol. The spin label, a pyrroline-1-oxyl radical, was highly immobilized after attachment to papain by both functional groups and showed little if any relative motion with respect to the protein.
Fachbereich Chemie, Universität Kaiserslautern, P.O. Box 3049, D-67653 Kaiserslautern, Germany.
R M
RM
Lösel
R
R
Philipp
T
T
Kálai
K
K
Hideg
W E
WE
Trommer
D003432:Cross-Linking Reagents; D004229:Dithiothreitol / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D007202:Indicators and Reagents; D008958:Models, Molecular; D010206:Papain / Q000737:chemistry; D010782:Photolysis; D013113:Spin Labels / Q000138:chemical synthesis*; D013439:Sulfhydryl Reagents / Q000737:chemistry
D003432:Cross-Linking Reagents; D007202:Indicators and Reagents; D013113:Spin Labels; D013439:Sulfhydryl Reagents; D010206:Papain; D004229:Dithiothreitol