Peptidic lipopolysaccharide (LPS) antagonists are the subject of intensive research. We reportan NMR and modeling study of LALF-14 (GCKPTFRRLKWKYKCG), a synthetic cyclizedfragment of the limulus anti-LPS factor (LALF) comprising residues 36−47. In a mixture withLPS we observed the transferred NOE effect and derived the LPS-bound structure of LALF-14. Neither the free nor the LPS-bound peptide displays NOEs indicative of a β-sheet-likestructure that is adopted by the fragment in the full-size protein. However, docking calculationsshow that the former structure is not a prerequisite for binding of LALF-14 to LPS.