Ion mobility and collision-induced dissociation analysis of carbonic anhydrase 2.
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.
Nabuchi
Yoshiaki
Y
Graduate School of Nanobioscience, Yokohama City University, Yokohama, Kanagawa 236-0027, Japan, and Technology Application Department, Nihon Waters K.K., Osaka, Osaka, 532-0011, Japan.
Hirose
Kenji
K
Takayama
Mitsuo
M
D000818:Animals; D024402:Carbonic Anhydrase II / Q000737:chemistry*; D002417:Cattle; D004912:Erythrocytes / Q000201:enzymology; D007477:Ions / Q000737:chemistry; D017510:Protein Folding; D011522:Protons; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
D007477:Ions; D011522:Protons; D024402:Carbonic Anhydrase II