Ion Mobility and Collision-Induced Dissociation Analysis of Carbonic Anhydrase 2

• Published in: Analytical chemistry (Washington) Vol. 82; no. 21; pp. 8890 - 8896
• Main Authors: Nabuchi, Yoshiaki, Hirose, Kenji, Takayama, Mitsuo
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.2010
• Subjects: Analytical chemistry; Animals; Carbonic Anhydrase II - chemistry; Cattle; Chemistry; Erythrocytes - enzymology; Exact sciences and technology; Ions; Ions - chemistry; Mass spectrometry; Protein Folding; Protons; Spectrometric and optical methods; Spectrometry, Mass, Electrospray Ionization - methods; Studies; Shift; Collisional activation; Enzyme; Product; Lyases; Precursor; Electrospray; Chemical ionization; Protein; Zinc; Ion mobility; Distribution; Production; Ion spectrometry; Carbonate dehydratase; Dissociation; Gas phase; Carbon-oxygen lyases; Hydro-lyases
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac101482b

Folding analysis of the zinc protein, carbonic anhydrase 2 (CA2), was performed using electrospray ionization ion mobility spectrometry coupled with collision-induced dissociation (ESI IMS/CID). Multiply protonated ions with a bimodal charge state distribution were observed indicating the presence of at least two folding states for gas-phase CA2 ions as was described in a previous study (Nabuchi, Y.; Murao, N.; Asoh, Y.; Takayama, M. Anal. Chem. 2007, 79, 8342−8349). In the IMS driftgram, several ions with different mobility were observed for each multiply charged ion, and this suggests that CA2 ions consist of several components with different folding states. IMS/CID spectra were acquired against precursor ions separated by mobility. The CID spectra gave several characteristic product ions including those from the N- and C-terminal region of CA2. A shift to larger charge number for the most abundant of the several product ions was observed for ions having a larger drift time. This charge number shift indicates that the folding state of the ion is more unfolded. Furthermore, differences in the production of an ion corresponding to the N-terminal side fragment gave information about the unfolding process of CA2.