| Abstrakt: |
The structure of four new pyoverdins (Pf12-IA, -IIA, -IB und IIB) isolated from the culture medium of Pseudomonas fluorescens 12 was elucidated by combination of spectroscopic methods and degradation reactions. The pyoverdins comprise (1 S)-5-amino-2,3-dihydro-8,9-dihydroxy-1 H-pyrimido[1,2-a]quinoline-1-carboxylic acid whose amino group carries a 3-carboxypropanoyl-(IA), succinamoyl- (IIA), 4-carboxy-4-oxobutanoyl- (IB) or L-4-amino-4-carboxybutanoylresidue (II B) and whose carboxyl group is bound amidically to the N-terminus of D-Ser-L-Lys-Gly-. According to the short-hand-nomenclature suggested in [2, 3] the pyoverdins may be described as pyoverdin-Q-sKGO′sSGK*o′ES*-SUC(IA), pyoverdin-Q-sKGO′sSGK*o′-ES*-SUCA (IIA), pyoverdin-Q-sKGO′sSGK*o′ES*-KGL (IB) and pyoverdin-Q-sKGO′sSGK*o′ES*-GLU (IIB). The pyoverdins described here possess the most complex structure encountered so far as their peptide part comprises eleven amino acids and the cyclo-tetrapeptide substructure. In addition, they are of special interest as for the first time glutamic acid could be identified as a chromophore side chain which is the key compound for the citric acid cycle to which belong all dicarboxylic acids found so far in pyoverdins. [ABSTRACT FROM AUTHOR] |
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