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Human recombinant [C22A] FK506‐binding protein amide hydrogen exchange rates from mass spectrometry match and extend those from NMR
Author(s) -
Zhang Zhongqi,
Li Weiqun,
Logan Timothy M.,
Li Ming,
Marshall Alan G.
Publication year - 1997
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560061015
Subject(s) - mass spectrometry , chemistry , amide , recombinant dna , nuclear magnetic resonance spectroscopy , stereochemistry , biochemistry , chromatography , gene
Hydrogen/deuterium exchange behavior of human recombinant [C22A] FK506 binding protein (C22A FKBP) has been determined by protein fragmentation, combined with electrospray Fourier transform ion cyclotron resonance mass spectrometry (MS). After a specified period of H/D exchange in solution, C22A FKBP was digested by pepsin under slow exchange conditions (pH 2.4, 0°C), and then subjected to on‐line HPLC/MS for deuterium analysis of each proteolytic peptide. The hydrogen exchange rate of each individual amide hydrogen was then determined independently by heteronuclear two‐dimensional NMR on 15 N‐enriched C22A FKBP. A maximum entropy method (MEM) algorithm makes it possible to derive the distributions of hydrogen exchange rate constants from the MS‐determined deuterium exchange‐in curves in either the holoprotein or its proteolytic segments. The MEM‐derived rate constant distributions of C22A FKBP and different segments of C22A FKBP are compared to the rate constants determined by NMR for individual amide protons. The rate constant distributions determined by both methods are consistent and complementary, thereby validating protein fragmentation/mass spectrometry as a reliable measure of hydrogen exchange in proteins.