title: Application of electrospray ionization mass spectrometry for studying human immunodeficiency virus protein complexes.
abstract: Mass spectrometry (MS) with electrospray ionization (ESI) has shown utility for studying noncovalent protein complexes, as it offers advantages in sensitivity, speed, and mass accuracy. The stoichiometry of the binding partners can be easily deduced from the molecular weight measurement. In many examples of protein complexes, the gas phase-based measurement is consistent with the expected solution phase binding characteristics. This quality suggests the utility of ESI-MS for investigating solution phase molecular interactions. Complexes composed of proteins from the human immunodeficiency virus (HIV) have been studied using ESI-MS. Multiply charged protein dimers from HIV integrase catalytic core (F185K) and HIV protease have been observed. Furthermore, the ternary complex between HIV protease dimer and inhibitor pepstatin A was studied as a function of solution pH. Zinc binding to zinc finger-containing nucleocapsid protein (NCp7) and the NCp7-psi RNA 1:1 stoichiometry complex was also studied by ESI-MS. No protein-RNA complex was observed in the absence of zinc, consistent with the role of the zinc finger motifs for RNA binding.
authors.affiliation: Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, Michigan 48105, USA. Joseph.Loo@wl.com
authors.forename: J A
authors.initials: JA
authors.lastname: Loo
authors.forename: T P
authors.initials: TP
authors.lastname: Holler
authors.forename: S K
authors.initials: SK
authors.lastname: Foltin
authors.forename: P
authors.initials: P
authors.lastname: McConnell
authors.forename: C A
authors.initials: CA
authors.lastname: Banotai
authors.forename: N M
authors.initials: NM
authors.lastname: Horne
authors.forename: W T
authors.initials: WT
authors.lastname: Mueller
authors.forename: T I
authors.initials: TI
authors.lastname: Stevenson
authors.forename: D P
authors.initials: DP
authors.lastname: Mack
mesh_terms: D000595:Amino Acid Sequence; D002213:Capsid / Q000737:chemistry / Q000378:metabolism*; D036022:Capsid Proteins; D019281:Dimerization; D015683:Gene Products, gag / Q000737:chemistry / Q000378:metabolism*; D019427:HIV Integrase / Q000737:chemistry / Q000378:metabolism*; D016333:HIV Protease / Q000737:chemistry / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000378:metabolism; D006801:Humans; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010436:Pepstatins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D014764:Viral Proteins; D015032:Zinc / Q000378:metabolism; D016335:Zinc Fingers; D054301:gag Gene Products, Human Immunodeficiency Virus
chemical_list: D036022:Capsid Proteins; D015683:Gene Products, gag; D017320:HIV Protease Inhibitors; C071884:NCP7 protein, Human immunodeficiency virus 1; D010436:Pepstatins; D014764:Viral Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; C014195:Streptomyces pepsin inhibitor; D012313:RNA; D019427:HIV Integrase; D016333:HIV Protease; D015032:Zinc; C031375:pepstatin