Unguisin C, a GABA-containing cyclic peptide from the fungus Emericella unguis.
Besides the known unguisins A and B, a new cyclic heptapeptide, unguisin C, containing a GABA-derived moiety in the ring, was isolated from the fungus Emericella unguis. The structure was determined by 1D and 2D NMR techniques. Marfey's method was used to determine the absolute stereochemistry. Precursor-directed biosynthesis of the unguisins was performed by supplementation of the culture medium with amino acids (L-Ala, L-Ser, L-Phe and L-Leu). A related cyclic heptapeptide, unguisin D, was detected by HPLC and characterized by sequence analysis using LC-QITMS.
Malmstrøm
Joan
J
Department of Structural Chemistry, Pharmaceuticals Development, Research and Development, Novo Nordisk A/S, Novo Nordisk Park, DK-2760 Maaloev, Denmark. joms@novonordisk.com
Ryager
Anne
A
Anthoni
Uffe
U
Nielsen
Per Halfdan
PH
D032842:Emericella / Q000737:chemistry*; D010456:Peptides, Cyclic / Q000737:chemistry / Q000302:isolation & purification*; D011487:Protein Conformation; D013057:Spectrum Analysis; D005680:gamma-Aminobutyric Acid / Q000737:chemistry*
D010456:Peptides, Cyclic; C470777:unguisin C; D005680:gamma-Aminobutyric Acid