MALDI-TOF Mass Spectrometry in the Protein Biochemistry Lab: From Characterization of Cell Cycle Regulators to the Quest for Novel Antibiotics

Abstract

For decades, direct covalent analysis was the only way to get the full primary structure of a protein, a tedious task involving several digests and exhaustive analysis [1]. More recently, this process has been accelerated by the use of limited sequence information to assist in cloning of the corresponding genes [2, 3]. Cloned DNA can be readily analyzed and the entire protein primary structure deduced. With a large number of genes sequenced and repositories rapidly expanding [4, 5], partial protein sequences have also allowed, with increasing frequency, matching biological function (or regulation) to a specific database entry [6–8]. The focus of protein sequencing has therefore again shifted to questions of protein associations in the cell. After discovery of one or more components of a functional complex (in signal transduction, cell cycle and differentiation, and vesicle targeting, among other processes), the question typically arises with which other proteins they might interact [9–11]. Since many of the targets are only available in minute quantities, it is imperative that analytical studies be carried out at the highest levels of sensitivity. Such pioneering applications challenge scientists and engineers, and drive technical developments. Frequently, multi-analytical approaches are taken to maximize accuracy. In this regard, it has been long foretold that mass spectrometry would attain a very prominent role in the protein chemistry lab.