Identification of phosphorylation and acetylation sites in αA-crystallin of the eye lens (mus musculus) after two-dimensional gel electrophoresis

摘要

Posttranslational modifications are of great interest because of their relevance in biological systems as proteins are commonly activated or deactivated by phosphorylation, glycation and acetylation 1,2. During eye lens aging the number of the αA-crystallin isoproteins increases. This could be observed by the use of 2D-PAGE (two-dimensional gel electrophoresis). The number of αA-crystallin spots in the gel increased during eye lens aging. For further analysis the spots of 2D-PAGE were cut out and the identification of the proteins was done using nanoLC-ESI-MS/MS (liquid chromatography electrospray ionization tandem mass spectrometry). The created MS/MS-data were analyzed using the Sequest algorithm. Searches with different parameters were done to preferably get the complete sequence coverage and to identify posttranslational modifications of the αA-crystallin. The acetylated N-terminus of this protein could be detected. Furthermore, phosphorylation of serine 122 and 148 was identified in two different spots.