The tetrapeptide Z‐Leu‐Aib‐Pro‐Val‐OBg monohydrate

The intramolecular hydrogen‐bonding pattern of Z‐Leu‐Aib‐Pro‐Val‐OBg monohydrate (N‐benzhydryl­amino)­carbonyl­methyl N‐benzyl­oxy­carbonyl‐α‐amino­isobutyryl­prolyl­valinate monohydrate], C₄₃H₅₅N₅O₈·H₂O, is unusual for a tetrapeptide because, in addition to a 14 hydrogen bond, a second hydrogen bond of the type 15 is formed. This folding reflects the intramolecular hydrogen‐bonding pattern that this amino acid sequence adopts in the naturally occurring peptaibol alamethicin.