title: Structure-activity relationships of the B fragment of diphtheria toxin: the lipid-binding domains.
abstract: Two different lipid-associating domains have previously been identified in diphtheria toxin fragment B: one of the surface type in the N-terminus of B and one of the transverse type in its middle region. We have now determined about 85% of the primary structure of fragment B and show, here, that the middle part of fragment B contains a highly hydrophobic region of 72 amino acid residues (polarity index: 295) which includes the transverse lipid-associating domain. That this domain is actually involved in a process of membrane penetration is suggested by lipid bilayer conductance measurements of the CNBr peptides of fragment B and trypsin treatment of fragment B-multilamellar liposome complexes.
mesh_terms: D000595:Amino Acid Sequence; D004134:Dimyristoylphosphatidylcholine; D004167:Diphtheria Toxin; D008081:Liposomes; D046911:Macromolecular Substances; D008954:Models, Biological; D010446:Peptide Fragments; D010713:Phosphatidylcholines; D013329:Structure-Activity Relationship
chemical_list: D004167:Diphtheria Toxin; D008081:Liposomes; D046911:Macromolecular Substances; D010446:Peptide Fragments; D010713:Phosphatidylcholines; D004134:Dimyristoylphosphatidylcholine