Photoinduced cell killing and crosslinking of fluorescein conjugated concanavalin A to cell surface proteins

Bleaching of fluorescein conjugated concanavalin A (F-Con A) labelled plasma membranes with 488 nm laser light leads to some broadening and a loss of protein bands and the appearance of high molecular weight material as shown by sodium dodecylsulfate polyacrylamide gel electrophoresis, indicating membrane protein crosslinking. The F-Con A is found throughout the high molecular weight regions linked to other proteins in large aggregates. Irradiation of whole cells labelled with F-Con A leads to cell death. These effects are dependent upon total light exposure and F-Con A concentration.