Trichotoxin A40. Purification by counter-current distribution and sequencing of isolated fragments.
The isolation of the membrane-modifying polypeptide antibiotics from the mycelium of Trichoderma viride 5242 was optimized via extraction with dichloromethane and chromatography on Sephadex LH-20. The components trichotoxin A40 and A50 were separated from each other and purified by multiplicative counter-current distribution. The sequence of proteinase-resistant trichotoxin A40 was determined by combined gas chromatography and mass spectrometry of three isolated N-acetylated dodecapeptides and two N-prolylhexapeptides obtained after selective trifluoroacetolysis. Including amino acid exchanges due to natural microheterogeneity, the sequence is Ac-Aib-Gly(LAla)-Aib-LLeu-Aib-LGln-Aib-Aib-Aib(LAla )-LAla-Aib-Aib-LPro-LLeu -Aib-DIva(Aib)-LGlu-LValol. In contrast to the eicosapeptide alamethicin, trichotoxin A40 contains only 18 residues, with a higher proportion of alpha-aminoisobutyric acid (Aib), C-terminal L-valinol (Vol), one D-isovaline (Iva) and no proline at the N-terminal part.
Brückner
H
H
König
W A
WA
Aydin
M
M
Jung
G
G
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000302:isolation & purification*; D003377:Countercurrent Distribution; D007473:Ion Channels; D003904:Mitosporic Fungi / Q000032:analysis*; D010455:Peptides / Q000302:isolation & purification; D013329:Structure-Activity Relationship; D014242:Trichoderma / Q000032:analysis*
D000900:Anti-Bacterial Agents; D007473:Ion Channels; D010455:Peptides; C077907:trichotoxin A40