Electrospray ionization mass spectrometry in the study of biomolecular non-covalent interactions

In the past mass spectrometry has been limited to the study of small, stabl e molecules, however, with the emergence of electrospray ionization mass sp ectrometry (ESI-MS) large biomolecules as well as non-covalent biomolecular complexes can be studied. ESI-MS has been used to study non-covalent inter actions involving proteins with metals, ligands, peptides, oligonucleotides , as well as other proteins. Although complementary to other well-establish ed techniques such as circular dichroism and fluorescence spectroscopy, ESI -MS offers some advantages in speed, sensitivity, and directness particular ly in the determination of the stoichiometry of the complex. One major adva ntage is the ability of ESI-MS to provide multiple signals each arising fro m a distinct population within the sample. In this review I will discuss so me of the different types of non-covalent biomolecular interactions that ha ve been studied using ESI-MS, highlighting examples which show the efficacy of using ESI-MS to probe the structure of biomolecular complexes. (C) 1999 Elsevier Science B.V. All rights reserved.