title: Crystal structure of an extended-conformation leucine-enkephalin dimer monohydrate.
abstract: The structure of a new crystal form of leucine-enkephalin has been determined by X-ray diffraction. There are two independent molecules in the asymmetric unit and both have extended peptide backbone conformations with side-chains arranged alternately above and below the backbone planes. The two pentapeptides are hydrogen-bonded to each other and to other molecules forming an extended antiparallel beta-pleated sheet. The structure differs from that in similar crystals of methionine enkephalin primarily in side-chain orientations and inter-sheet interactions.
mesh_terms: D003460:Crystallization; D004743:Enkephalin, Leucine; D004744:Enkephalin, Methionine; D008958:Models, Molecular; D011487:Protein Conformation; D014961:X-Ray Diffraction
chemical_list: D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine