Toward oxygen binding curves of single respiratory proteins.
Oxygen binding curves of single molecules promise to discriminate between different models describing cooperativity because load distributions are accessible. Individual tarantula hemocyanins could be detected by fluorescence correlation spectroscopy using intrinsic tryptophan fluorescence as sensor of bound oxygen. However, imaging of immobilized proteins was not possible due to fast photo-bleaching. It is shown that tetra-methyl-carboxy-rhodamine (TAMRA), commonly used as a fluorescence label in single-molecule spectroscopy, can also be applied to monitor bound oxygen. The dye's fluorescence is quenched due to Förster energy transfer to the oxygenated active sites of hemocyanin.
Erker
Wolfgang
W
Institute for Physical Chemistry, University of Mainz, Welderweg 11, Mainz 55128, Germany. erker@mail.uni-mainz.de
Lippitz
Markus
M
Basché
Thomas
T
Decker
Heinz
H
D000818:Animals; D005456:Fluorescent Dyes; D006433:Hemocyanins / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D012235:Rhodamines / Q000378:metabolism; D013112:Spiders
C114557:5-carboxytetramethylrhodamine succinimidyl ester; D005456:Fluorescent Dyes; D012235:Rhodamines; D006433:Hemocyanins; D010100:Oxygen