title: Relationship between the tertiary structures of mastoparan B and its analogs and their lytic activities studied by NMR spectroscopy.
abstract: Mastoparan B (MP-B), an antimicrobial cationic tetradecapeptide amide isolated from the venom of the hornet Vespa basalis, is an amphiphilic alpha-helical peptide. MP-B possesses a variety of biological activities, such as mast cells degradation histamine release, erythrocyte lysis and inhibition of the growth of gram-positive and gram-negative bacteria. In order to study the relationship between the structure and the biological activity of MP-B, we used four analogs by replacing amino acids with alanine. Tertiary structures of MP-B and its analogs in 2,2,2-trifluoroethanol (TFE)-containing aqueous solution have been determined by NMR spectroscopy and molecular modeling. The results indicate that [Ala4]MP-B and [Ala12]MP-B with higher hydrophobicity adopt a higher content of amphiphilic helical structures, and have better antimicrobial and hemolytic activities than MP-B. However, [Ala3]MP-B and [Ala9]MP-B with lower hydrophobicity have disordered structures. [Ala3]MP-B and [Ala9]MP-B have low antimicrobial activity and much less hemolytic activity relative to MP-B. It is likely that tryptophan residue in MP-B and appropriate hydrophobicity of MP-B to induce alpha-helical structure is essential for the antibacterial and hemolytic activity of MP-B. This study can aid understanding of the structure-activity relationship of MP-B and to design peptides to possess lytic activity.
authors.affiliation: Department of Chemistry, Konkuk University, Seoul, Korea.
authors.forename: K
authors.initials: K
authors.lastname: Yu
authors.forename: S
authors.initials: S
authors.lastname: Kang
authors.forename: N
authors.initials: N
authors.lastname: Park
authors.forename: J
authors.initials: J
authors.lastname: Shin
authors.forename: Y
authors.initials: Y
authors.lastname: Kim
mesh_terms: D000409:Alanine; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D002942:Circular Dichroism; D006460:Hemolysin Proteins / Q000737:chemistry / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D017434:Protein Structure, Tertiary; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D006460:Hemolysin Proteins; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; C081223:mastoparan B; D000409:Alanine