Electrospray ionization mass spectrometry for the study of non-covalent complexes: an emerging technology.
The detection of non-covalent complexes in the mass range 19,000-34,000 Da, using electrospray ionization mass spectrometry (ESI-MS), is reviewed. The examples discussed include (1) a protein-ligand interaction (ras-GDP), (2) an inhibitor-protein-ligand interaction (SCH 54292/SCH 54341-ras-GDP), (3) a protein-protein interaction (gamma-IFN homodimer) and (4) a protein-metal complex [HCV (1-181)-Zn]. In each case, the ESI-MS method is capable of releasing the intact non-covalent complex from its native solution state into the gas phase in the form of multiply-charge ions. The molecular masses of these complexes were determined with a mass accuracy of better than 0.01%, which is far superior to the traditional methods of sodium dodecyl sulfate polyacrylamide gel electrophoresis and gel permeation chromatography. The method provides the researcher with a quick, reliable and reproducible method for probing difficult biological problems. The key to success in the study of non-covalent complexes depends on careful understanding and manipulation of ESI source parameters and sample solution conditions; special care must be taken with the source orifice potential and the solution pH and organic co-solvents must be avoided. This paper also illustrates the usefulness of ESI-MS for addressing biological problems leading to the discovery of new therapeutics; the approach involves the rapid screening of potential drug candidates, such as weakly bound inhibitors.
Pramanik
B N
BN
Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA.
Bartner
P L
PL
Mirza
U A
UA
Liu
Y H
YH
Ganguly
A K
AK
D002614:Chelating Agents / Q000737:chemistry; D011905:Genes, ras; D005960:Glucosides / Q000032:analysis; D006153:Guanosine Diphosphate / Q000032:analysis; D016174:Hepacivirus / Q000737:chemistry; D006801:Humans; D007371:Interferon-gamma / Q000737:chemistry; D008024:Ligands; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D008670:Metals / Q000737:chemistry; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis / Q000737:chemistry*; D013449:Sulfonamides / Q000032:analysis
D002614:Chelating Agents; D005960:Glucosides; D008024:Ligands; D008670:Metals; D011506:Proteins; C107861:SCH 54292; D013449:Sulfonamides; D006153:Guanosine Diphosphate; D007371:Interferon-gamma