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. Author manuscript; available in PMC: 2020 May 11.
Published in final edited form as: ACS Infect Dis. 2019 Dec 12;6(2):291–301. doi: 10.1021/acsinfecdis.9b00355

Fig 6. MS2 fragmentation of succinylated Ara4.

Fig 6.

(m/z 645 (M-H)1−; 1a) and the location of the succinyl substitution. Different pathways of fragmentation have been described with representative ions 1b-e.. i) A-type ion at m/z 143 corresponds to the structure 1f. It shows the location of the succinyl residue (after α-cleavage) at the non-reducing side of Araf unit. Only two possibilities identified; one, terminal β-linked Araf; two, 2-glycosylated penultimate Araf. ii) The ion at m/z 213, corresponding to 1g, shows that the succinyl residue is at the 3-position of the 2-glycosylated Araf. iii) The ion at m/z 113 is characteristic of furan ring formation. iv & v) The ions at m/z 527 and 545 supports the loss of a succinyl residue attached to a secondary –OH group. vi) The ion m/z 537 and its assigned structure signifying terminal Araf has unsubstituted 3-and 5-OH groups. vii) Plausible mechanism of formation of m/z 113 through a γ-elimination, common in CID-MS2.