| METHOD |
A new method known as protein correlation profiling overcomes the problem in proteomics of distinguishing proteins that are part of a complex from other proteins. This method could be applied to the analysis of any protein complex. For example, a team led by Matthias Mann, a professor in the department of biochemistry and molecular biology at the University of Southern Denmark in Odense, and Erich A. Nigg, director of the cell biology department at Max Planck Institute for Biochemistry in Martinsried, Germany, has applied the method to characterize the centrosome [Nature, 426, 570 (2003)]. The centrosome serves as the organizational center of microtubules in cells and is involved in cell division, in which it is located at the ends of the mitotic spindle that segregates duplicated chromosomes between the daughter cells. In this mass-spectrometry-based method, hundreds of peptides are tracked through five different centrifugation fractions of the centrosome preparation. Relative, but not absolute, amounts of identical peptides can be determined in analyses of different fractions. Centrosomal and contaminating proteins have very different fractionation profiles. The team identified and validated 23 previously unknown centrosome proteins and identified 41 other candidate proteins using this method
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