TY - JOUR
T1 - Characterization of Cardiolipin as the Sodiated Ions by Positive-Ion Electrospray Ionization with Multiple Stage Quadrupole Ion-Trap Mass Spectrometry
AU - Hsu, Fong Fu
AU - Turk, John
N1 - Funding Information:
This research was supported by U.S. Public Health Service grants P41-RR-00,954, R37-DK-34,388, P60-DK-20,579, P01-HL-57,278, P30-DK-56,341, and a grant (996003) from the Juvenile Diabetes Foundation.
PY - 2006/8
Y1 - 2006/8
N2 - The application of multiple-stage ion-trap (IT) mass spectrometric methods for the structural characterization of cardiolipin (CL), a 1,3-bisphosphatidyl-sn-glycerol that consists of four fatty acyl chains and three glycerol backbones (designated as A, B, and central glycerol, respectively), as the sodiated adduct ions in the positive-ion mode was evaluated. Following collisionally activated dissociation (CAD), the [M - 2H + 3Na]+ ions of CL yield two prominent fragment ion pairs that consist of the phosphatidyl moieties attached to the 1′- and 3′-position of the central glycerol, respectively, resulting from the differential losses of the diacylglycerol moieties containing A and B glycerol, respectively. The results are consistent with those previously described for the [M - H]- and [M - 2H + Na]- ions in the negative-ion mode, thus permitting assignment of the two phosphatidyl moieties attached to the 1′- or 3′-position of the central glycerol. The identities of the fatty acyl substituents and their positions on the glycerol backbones (glycerol A and B) are deduced from further degradation of the above ion pairs that give the fragment ions reflecting the fatty acid substituents at the sn-1 (or sn-1′) and sn-2 (or sn-2′) positions. The ions that arise from losses of the fatty acid substituents at sn-1 and sn-1′, respectively, are prominent, but the analogous ions from losses of the fatty acid substituents at sn-2 and sn-2′, respectively, are of low abundance in the MS2 product-ion spectra. This feature further confirms the assignment of the positions of the fatty acid substituents. The similar IT multiple-stage mass spectrometric approaches including MS2 and MS3 for structural characterization of CL using its [M + Na]+ and the [M - H + 2Na]+ ions are also readily applicable. However, their uses for structural characterization are less desirable because formation of the [M + Na]+ and the [M - H + 2Na]+ ions for CL is not predictable.
AB - The application of multiple-stage ion-trap (IT) mass spectrometric methods for the structural characterization of cardiolipin (CL), a 1,3-bisphosphatidyl-sn-glycerol that consists of four fatty acyl chains and three glycerol backbones (designated as A, B, and central glycerol, respectively), as the sodiated adduct ions in the positive-ion mode was evaluated. Following collisionally activated dissociation (CAD), the [M - 2H + 3Na]+ ions of CL yield two prominent fragment ion pairs that consist of the phosphatidyl moieties attached to the 1′- and 3′-position of the central glycerol, respectively, resulting from the differential losses of the diacylglycerol moieties containing A and B glycerol, respectively. The results are consistent with those previously described for the [M - H]- and [M - 2H + Na]- ions in the negative-ion mode, thus permitting assignment of the two phosphatidyl moieties attached to the 1′- or 3′-position of the central glycerol. The identities of the fatty acyl substituents and their positions on the glycerol backbones (glycerol A and B) are deduced from further degradation of the above ion pairs that give the fragment ions reflecting the fatty acid substituents at the sn-1 (or sn-1′) and sn-2 (or sn-2′) positions. The ions that arise from losses of the fatty acid substituents at sn-1 and sn-1′, respectively, are prominent, but the analogous ions from losses of the fatty acid substituents at sn-2 and sn-2′, respectively, are of low abundance in the MS2 product-ion spectra. This feature further confirms the assignment of the positions of the fatty acid substituents. The similar IT multiple-stage mass spectrometric approaches including MS2 and MS3 for structural characterization of CL using its [M + Na]+ and the [M - H + 2Na]+ ions are also readily applicable. However, their uses for structural characterization are less desirable because formation of the [M + Na]+ and the [M - H + 2Na]+ ions for CL is not predictable.
UR - http://www.scopus.com/inward/record.url?scp=33746268123&partnerID=8YFLogxK
U2 - 10.1016/j.jasms.2006.04.024
DO - 10.1016/j.jasms.2006.04.024
M3 - Article
C2 - 16750386
AN - SCOPUS:33746268123
SN - 1044-0305
VL - 17
SP - 1146
EP - 1157
JO - Journal of the American Society for Mass Spectrometry
JF - Journal of the American Society for Mass Spectrometry
IS - 8
ER -