@article {2390,
	title = {Effect of Membrane Composition on Antimicrobial Peptides Aurein 2.2 and 2.3 From Australian Southern Bell Frogs},
	journal = {Biophysical Journal},
	volume = {96},
	number = {2},
	year = {2009},
	note = {ISI Document Delivery No.: 450BYTimes Cited: 8Cited Reference Count: 96Cheng, John T. J. Hale, John D. Elliot, Melissa Hancock, Robert E. W. Straus, Suzana K.},
	month = {Jan},
	pages = {552-565},
	type = {Article},
	abstract = {The effects of hydrophobic thickness and the molar phosphatidylglycerol (PG) content of lipid bilayers on the structure and membrane interaction of three cationic antimicrobial peptides were examined: aurein 2.2, aurein 2.3 (almost identical to aurein 2.2, except for a point mutation at residue 13), and a carboxy C-terminal analog of aurein 2.3. Circular dichroism results indicated that all three peptides adopt an a-helical structure in the presence of a 3:1 molar mixture of 1,2-dimyristoyi-sn-glycero3-phosphocholine/1,2-dimyristoyi-sn-glycero-3- [phospho-rac-(1-glycerol)] (DMPC/DMPG), and 1:1 and 3:1 molar mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1-paimitoyl-2-oleoyl-sn -glycero-3-[phospho-rac-(1-glycerol)] (POPC/POPG). Oriented circular dichroism data for three different lipid compositions showed that all three peptides were surface-adsorbed at low peptide concentrations, but were inserted into the membrane at higher peptide concentrations. The (31)p solid-state NMR data of the three peptides in the DMPC/DMPG and POPC/POPG bilayers showed that all three peptides significantly perturbed lipid headgroups, in a peptide or lipid composition-dependent manner. Differential scanning calorimetry results demonstrated that both amidated aurein peptides perturbed the overall phase structure of DMPC/DMPG bilayers, but perturbed the POPC/POPG chains less. The nature of the perturbation of DMPC/DMPG bilayers was most likely micellization, and for the POPC/POPG bilayers, distorted toroidal pores or localized membrane aggregate formation. Calcein release assay results showed that aurein peptide-induced membrane leakage was more severe in DMPC/DMPG liposomes than in POPC/POPG liposomes, and that aurein 2.2 induced higher calcein release than aurein 2.3 and aurein 2.3-COOH from 1:1 and 3:1 POPC/POPG liposomes. Finally, DiSC(3)5 assay data further delineated aurein 2.2 from the others by showing that it perturbed the lipid membranes of intact S. aureus C622 most efficiently, whereas aurein 2.3 had the same efficiency as gramicidin S, and aurein 2.3-COOH was the least efficient. Taken together, these data show that the membrane interactions of aurein peptides are affected by the hydrophobic thickness of the lipid bilayers and the PG content.},
	keywords = {ANTIBIOTIC PEPTIDES, CIRCULAR-DICHROISM SPECTROSCOPY, HOST-DEFENSE PEPTIDES, LIPID-COMPOSITION, MEMBRANES, MODEL, PHOSPHOLIPID-BILAYER MEMBRANES, PROTEIN SECONDARY STRUCTURE, SOLID-STATE NMR, STAPHYLOCOCCUS-AUREUS, TREE-FROG},
	isbn = {0006-3495},
	url = {<Go to ISI>://000266377200025},
	author = {Cheng, J. T. J. and Hale, J. D. and Elliot, M. and Hancock, R. E. W. and Straus, S. K.}
}
@article {3956,
	title = {High-resolution NMR structure and backbone dynamics of the Bacillus subtilis response regulator, SpoOF: Implications for phosphorylation and molecular recognition},
	journal = {Biochemistry},
	volume = {36},
	number = {33},
	year = {1997},
	note = {ISI Document Delivery No.: XR735Times Cited: 45Cited Reference Count: 78},
	month = {Aug},
	pages = {10015-10025},
	type = {Article},
	abstract = {NMR has been employed for structural and dynamic studies of the bacterial response regulator, SpoOF. This 124-residue protein is an essential component of the sporulation phosphorelay signal transduction pathway in Bacillus subtilis. Three-dimensional H-1, N-15, and C-13 experiments have been used to obtain full side chain assignments and the 1511 distance, 121 dihedral angle, and 80 hydrogen bonding restraints required for generating a family of structures (14 restraints per residue). The structures give a well-defined (alpha/beta)(5) fold for residues 4-120 with average rms deviations of 0.59 Angstrom for backbone heavy atoms and 1.02 Angstrom for all heavy atoms. Analyses of backbone N-15 relaxation measurements demonstrate relative rigidity in most regions of regular secondary structure with a generalized order parameter (S-2) Of 0.9 +/- 0.05 and a rotational correlation time (tau(m)) of 7.0 +/- 0.5 ns, Loop regions near the site of phosphorylation have higher than average rms deviation values and T-1/T-2 ratios suggesting significant internal motion or chemical exchange at these sites, Additionally, multiple conformers are observed for the beta 4-alpha 4 loop and beta-strand 5 region, These conformers may be related to structural changes associated with phosphorylation and also indicative of the propensity this recognition surface has for differential protein interactions. Comparison of SpoOF structural features to those of other response regulators reveals subtle differences in the orientations of secondary structure in the putative recognition surfaces and the relative charge distribution of residues surrounding the site of phosphorylation, These may be important in providing specificity for protein-protein interactions and for determining the lifetimes of the phosphorylated state.},
	keywords = {3-DIMENSIONAL STRUCTURE, BACTERIAL CHEMOTAXIS, C-13 MAGNETIZATION, C-13-ENRICHED PROTEINS, C-13-LABELED PROTEINS, ESCHERICHIA-COLI, MAGNESIUM-BINDING, NUCLEAR-MAGNETIC-RESONANCE, PROTEIN SECONDARY STRUCTURE, SIGNAL-TRANSDUCTION},
	isbn = {0006-2960},
	url = {<Go to ISI>://A1997XR73500007},
	author = {Feher, V. A. and Zapf, J. W. and Hoch, J. A. and Whiteley, J. M. and McIntosh, L. P. and Rance, M. and Skelton, N. J. and Dahlquist, F. W. and Cavanah, J.}
}
