Micelle-bound Structures and Dynamics of the Hinge Deleted Analog of Melittin and Its Diastereomer: Implications in Cell Selective Lysis by D-amino acid Containing Antimicrobial Peptides Export

@article{citeulike:5275679, abstract = {Melittin, the major component of the homey bee venom, is a 26-residue hemolytic and membrane active peptide. Structures of melittin determined either in lipid environments by NMR or by use of x-ray demonstrated two helical regions at the N- and C-termini connected by a hinge or a bend at the middle. Here, we show that deletion of the hinge residues along with two C-terminal terminal Gln residues (Q25 and Q26), yielding a peptide analog of 19-residue or Mel-H, did not affect antibacterial activity but resulted in somewhat reduction in hemolytic activity. A diastereomer of Mel-H or Mel- d H containing d-amino acids [ d V5, d V8, d L11 and d K16] showed further reduction in hemolytic activity without lowering antibacterial activity. We have carried out NMR structures, dynamics (H-D exchange and proton relaxation), membrane localization by spin labeled lipids, pulse-field-gradient (PFG) NMR and isothermal titration calorimetry (ITC) in dodecylphosphocholine (DPC) micelles, as a mimic to eukaryotic membrane, to again insights into cell selectivity of these melittin analogs. PFG-NMR showed Mel-H and Mel- d H both were similarly partitioned into DPC micelles. ITC demonstrated Mel-H and Mel- d H interacts with DPC with similar affinity. Micelle-bound structure of Mel-H delineated a straight helical conformation, whereas Mel- d H showed multiple β-turns at the N-terminus and a short helix at the C-terminus. The backbone amide-proton exchange with solvent D 2 O demonstrated a large difference in dynamics between Mel-H and Mel- d H, whereby almost all backbone protons of Mel- d H showed a much faster rate of exchange as compared to Mel-H. Proton T 1 relaxation had suggested a mobile backbone of Mel- d H peptide in DPC micelles. Resonance perturbation by paramagnetic lipids indicated that Mel-H inserted deeper into DPC micelles, whereas Mel- d H is largely located at the surface of the micelle. Taken together, results presented in this study demonstrated that the poor hemolytic activity of the d-amino acid containing analogs of antimicrobial peptides may be correlated with their flexible dynamics at the membrane surface.}, author = {Saravanan, Rathi and Bhunia, Anirban and Bhattacharjya, Surajit}, citeulike-article-id = {5275679}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.bbamem.2009.07.014}, citeulike-linkout-1 = {http://linkinghub.elsevier.com/retrieve/pii/S0005273609002417}, day = {25}, doi = {10.1016/j.bbamem.2009.07.014}, issn = {00052736}, journal = {Biochimica et Biophysica Acta (BBA) - Biomembranes}, keywords = {dynamics, melittin, membrane, micelle, sarava09pdf, selectivity, strucutre}, month = {July}, posted-at = {2009-07-27 01:25:02}, priority = {2}, title = {Micelle-bound Structures and Dynamics of the Hinge Deleted Analog of Melittin and Its Diastereomer: Implications in Cell Selective Lysis by D-amino acid Containing Antimicrobial Peptides}, url = {http://dx.doi.org/10.1016/j.bbamem.2009.07.014}, year = {2009} }

TY - JOUR ID - citeulike:5275679 L3 - citeulike-article-id:5275679 N2 - Melittin, the major component of the homey bee venom, is a 26-residue hemolytic and membrane active peptide. Structures of melittin determined either in lipid environments by NMR or by use of x-ray demonstrated two helical regions at the N- and C-termini connected by a hinge or a bend at the middle. Here, we show that deletion of the hinge residues along with two C-terminal terminal Gln residues (Q25 and Q26), yielding a peptide analog of 19-residue or Mel-H, did not affect antibacterial activity but resulted in somewhat reduction in hemolytic activity. A diastereomer of Mel-H or Mel- d H containing d-amino acids [ d V5, d V8, d L11 and d K16] showed further reduction in hemolytic activity without lowering antibacterial activity. We have carried out NMR structures, dynamics (H-D exchange and proton relaxation), membrane localization by spin labeled lipids, pulse-field-gradient (PFG) NMR and isothermal titration calorimetry (ITC) in dodecylphosphocholine (DPC) micelles, as a mimic to eukaryotic membrane, to again insights into cell selectivity of these melittin analogs. PFG-NMR showed Mel-H and Mel- d H both were similarly partitioned into DPC micelles. ITC demonstrated Mel-H and Mel- d H interacts with DPC with similar affinity. Micelle-bound structure of Mel-H delineated a straight helical conformation, whereas Mel- d H showed multiple β-turns at the N-terminus and a short helix at the C-terminus. The backbone amide-proton exchange with solvent D 2 O demonstrated a large difference in dynamics between Mel-H and Mel- d H, whereby almost all backbone protons of Mel- d H showed a much faster rate of exchange as compared to Mel-H. Proton T 1 relaxation had suggested a mobile backbone of Mel- d H peptide in DPC micelles. Resonance perturbation by paramagnetic lipids indicated that Mel-H inserted deeper into DPC micelles, whereas Mel- d H is largely located at the surface of the micelle. Taken together, results presented in this study demonstrated that the poor hemolytic activity of the d-amino acid containing analogs of antimicrobial peptides may be correlated with their flexible dynamics at the membrane surface. JF - Biochimica et Biophysica Acta (BBA) - Biomembranes SN - 00052736 TI - Micelle-bound Structures and Dynamics of the Hinge Deleted Analog of Melittin and Its Diastereomer: Implications in Cell Selective Lysis by D-amino acid Containing Antimicrobial Peptides KW - dynamics KW - melittin KW - membrane KW - micelle KW - sarava09pdf KW - selectivity KW - strucutre AU - Saravanan, Rathi AU - Bhunia, Anirban AU - Bhattacharjya, Surajit PY - 2009/07/25/ UR - http://dx.doi.org/10.1016/j.bbamem.2009.07.014 ER -