| Autor: |
Tilvi S; 1 Bio-Organic Chemistry Laboratory, Chemical Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa, India., Devi P; 1 Bio-Organic Chemistry Laboratory, Chemical Oceanography Division, CSIR-National Institute of Oceanography, Dona Paula, Goa, India., Majik MS; 2 Department of Chemistry, Goa University, Taleigao-Plateau, Goa, India. |
| Jazyk: |
angličtina |
| Zdroj: |
European journal of mass spectrometry (Chichester, England) [Eur J Mass Spectrom (Chichester)] 2017 Jun; Vol. 23 (3), pp. 92-97. Date of Electronic Publication: 2017 Mar 30. |
| DOI: |
10.1177/1469066717699218 |
| Abstrakt: |
Butanol fraction of sacoglossan Elysia grandifolia was investigated for identifying peptides using electrospray ionisation-tandem mass spectrometry (ESI-MS/MS). Without prior isolation, the structural determination is achieved on the basis of mass fragmentation pattern and comparison with the previously established data. The ESI-MS of the fraction in the positive ion mode gave clusters of singly and doubly charged molecular ion peaks. The ESI-MS spectrum showed peaks for the presence of the peptides kahalalides F, G, R and S reported earlier. In addition, it also showed molecular ion peaks at m/z 1557.8 [M+H] + and doubly charged ions at m/z 779.4 [M+2H] 2+ , 790.4 [M+Na] 2+ and 796.4 [M+K] 2+ . The MS/MS at m/z 779.4 [M+2H] +2 at collision energy 40 V obtained series of b and y fragment ions. The MS/MS spectrum showed identical fragment ion y 6 at m/z 643 which revealed that cyclic part is identical with kahalalide F, R and S. Careful examination of the fragment ions b 1 to b 7 with their corresponding y fragment ions y 12 to y 6 , respectively and by comparison of MS/MS pattern of kahalalide S, established that proline can be replaced by tyrosine amino acid residue. The mass difference between b 4 ( m/z 511) and b 5 ( m/z 674) is equal to 163 which is equivalent to mass residue of tyrosine. Their y fragment ions also quickly helped in fixing the puzzle. This resulted in the identification of the peptide sequence cyclo-[Val-(5-MeHex-Val-Thr-Val-Val-Tyr-Lys-Ile)Thr-Ile-Val-Phe-Dhb)] for the new cyclodepsipeptide, kahalalide Z 3 . Thus, ESI-MS/MS has set a trend in quick identification of new marine molecules. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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