Toward the bilayer proteome, electrospray ionization-mass spectrometry of large, intact transmembrane proteins.
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Whitelegge JP, le Coutre J, Lee JC, Engel CK, Prive GG, Faull KF, Kaback HR
Toward the bilayer proteome, electrospray ionization-mass spectrometry of large, intact transmembrane proteins.
Proc Natl Acad Sci U S A. 1999 Sep 14;96(19):10695-8.
- PubMed ID
- 10485888 [ View in PubMed]
- Abstract
Genes encoding membrane proteins comprise a substantial proportion of genomes sequenced to date, but ability to perform structural studies on this portion of the proteome is limited. Electrospray ionization-MS (ESI-MS) of an intact protein generates a profile defining the native covalent state of the gene product and its heterogeneity. Here we apply ESI-MS technology with accuracy exceeding 0.01% to a hydrophobic membrane protein with 12-transmembrane alpha-helices, the full-length lactose permease from Escherichia coli. Furthermore, ESI-MS is used to titrate reactive thiols with N-ethylmaleimide. Treatment of the native protein solubilized in detergent micelles reveals only two reactive thiols, and both are protected by a substrate analog.