Detection of new amino acid sequences of alamethicins F30 by nonaqueous capillary electrophoresis-mass spectrometry.
The microheterogeneous alamethicin F30 (ALM F30) isolated from the fermentation of Trichoderma viride strain NRRL 3199 was analyzed by nonaqueous capillary electrophoresis coupled to electrospray ion-trap mass spectrometry (ESI-IT-MS) and electrospray time-of-flight mass spectrometry (ESI-TOF-MS). Tandem ESI-IT-MS was used for elucidation of the amino acid sequence based on the fragmentation pattern of selected parent ions. The MS/MS spectra using the [M + 3H](3+) or [M + 2H](2+) ions as precursor ions displayed the respective b- and the y-type fragments resulting from cleavage of the particularly labile Aib-Pro bond. The MS(3) of these fragments generated the b acylium ion series, as well as internal fragment ion series. Eleven amino acid sequences were identified, characterized by the exchange of Ala to Aib in position 6, Gln to Glu in positions 7 or 19 as well as the loss of the C-terminal amino alcohol. In addition, two truncated pyroglutamyl peptaibols were found. Overall, seven new sequences are reported compared to earlier LC-MS studies. The composition of the components was confirmed by on-line ESI-TOF-MS detection. Mass accuracy well below 5 ppm was observed. Quantification of the individual components was achieved by a combination of UV and TOF-MS detection.
Psurek
Arndt
A
University of Jena, School of Pharmacy, Department of Pharmaceutical Chemistry, Germany.
Neusüss
Christian
C
Degenkolb
Thomas
T
Brückner
Hans
H
Balaguer
Elvira
E
Imhof
Diana
D
Scriba
Gerhard K E
GK
D000408:Alamethicin / Q000032:analysis / Q000737:chemistry*; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D000900:Anti-Bacterial Agents; D010446:Peptide Fragments; D012997:Solvents; D000408:Alamethicin