Novel Glycerophospholipid, Lipo- and -acyl Amino Acids from Bacteroidetes: Isolation, Structure Elucidation and Bioactivity.

The 'core' metabolome of the Bacteroidetes genus was recently discovered to consist of only seven metabolites. A structural relationship in terms of shared lipid moieties among four of them was postulated. Here, structure elucidation and characterization via ultra-high resolution mass spectrometry (UHR-MS) and nuclear magnetic resonance (NMR) spectroscopy of those four lipids (two lipoamino acids (LAAs), two lysophosphatidylethanolamines (LPEs)), as well as several other undescribed LAAs and -acyl amino acids (NAAAs), identified during isolation were carried out. The LAAs represent closely related analogs of the literature-known LAAs, such as the glycine-serine dipeptide lipids 430 () and 654. Most of the here characterized LAAs (, -) are members of a so far undescribed glycine-serine-ornithine tripeptide lipid family. Moreover, this study reports three novel NAAAs (-(5-methyl)hexanoyl tyrosine () and -(7-methyl)octanoyl tyrosine () or phenylalanine ()) from sp. FHG000416, another Bacteroidetes strain initially selected as best in-house producer for isolation of lipid 430. Antimicrobial profiling revealed most isolated LAAs (-) and the two LPE 'core' metabolites (, ) active against the Gram-negative pathogen ATCC 25238 and the Gram-positive bacterium DSM 20030. For LAA , additional growth inhibition activity against DSM 10 was observed.