Characterization of cytochrome c variants with high-resolution FTICR mass spectrometry. Correlation of fragmentation and structure

Journal Article · Sat Jul 15 04:00:00 EDT 1995 · Analytical Chemistry (Washington)

DOI:https://doi.org/10.1021/ac00110a027· OSTI ID:81686

Wu, Q; Orden, S V; Cheng, X; Bakhtiar, R; Smith, R D ^[1]

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1. Pacific Northwest Lab., Richland, WA (United States)

The dissociation of cytochrome c ions (15+ charge state) generated by electrospray ionization has been studied by Fourier transform ion cyclotron resonance mass spectrometry (FTICR) using a sustained off-resonance irradiation/collision-induced dissociation (SORI-CID) technique. Over 95% of the fragment ions can be accurately assigned (to better than 10 ppm), yielding information on the primary sequences of the various proteins. Of particular importance are a variety of results indicating that the dissociation of the cytochrome c`S is influenced by higher-order structure and charge location, in addition to the primary structure (i.e., sequence). No fragmentation is observed in the region between residues 10-20 and little dissociation between residues 70-90. This is most likely due to the interactions of the heme group with the polypeptide chain, and such a heme `footprinting` pattern is analogous to the protein conformation in solution. These studies demonstrate that electrospray ionization-FTICR using SORI-CID can be a useful tool to probe not only the small differences in the primary sequences of proteins but also suggest the potential for probing their higher-order structures and yielding information not readily available from H/D exchange or circular dichroism studies. 73 refs., 9 figs., 2 tabs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 81686
• Journal Information: Analytical Chemistry (Washington), Journal Name: Analytical Chemistry (Washington) Journal Issue: 14 Vol. 67; ISSN ANCHAM; ISSN 0003-2700
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
55 BIOLOGY AND MEDICINE
BASIC STUDIES
66 PHYSICS
CYTOCHROMES
DISSOCIATION
FRAGMENTATION
ION CYCLOTRON-RESONANCE
ION-MOLECULE COLLISIONS
IONIZATION
MASS SPECTRA
MASS SPECTROMETERS
MOLECULAR STRUCTURE
PROTEINS
QUANTITATIVE CHEMICAL ANALYSIS