R. Nagaraj

The crystal and molecular structure of the amino terminal tetrapeptide of alamethicin. A novel 310 helical conformation

The molecular structure of N-benzyloxycarbonyl-α-aminoisobutyryl-prolyl-α-aminoisobutyryl-alanyl methyl ester (Z-Aib-Pro-Aib-Ala-OMe), the amino terminal tetrapeptide of alamethicin is reported. The molecule contains two consecutive β-turns with Aib-Pro and Pro-Aib at the corners, forming an incipient 310 helix. This constitutes the first example of an X2-Pro3 β-turn in the crystal structure of a small peptide.

Infrared spectroscopy as a probe for the development of secondary structure in the amino-terminal segment of alamethicin

Peptides containing \alpha-aminoisobutyryl (Aib) residues have been shown to adopt well-defined structures in solution, by 1H NMR methods [1]. Theoretical studies suggest that the presence of geminal methyl substituents at

Hydrophobic channels in crystals of an α-aminoisobutyric acid pentapeptide

C^{\alpha}

Alamethicin and synthetic peptide fragments as uncouplers of mitochondrial oxidative phosphorylation. Effect of chain length and change

imposes severe restrictions on the conformations accessible to Aib residues [2,3]. Single crystal X-ray diffraction studies of Z-Aib-Pro-NHMe[4], Z-Aib-Pro-Aib-Ala-OMe [5] and

Cation Translocating Effects of Alamethicin and its Synthetic Fragments in Lipid Membranes: Influence of peptide chain length and charge

Tosyl-{(Aib)}_5-OMe

A stereochemically-constrained enkephalin analog: α-Aminoisobutyryl2 methionine5 enkephalinamide

[6] have clearly established the tendency of Aib residues to adopt

Enkephalin Analogs. Introduction of Stereochemical Constraints, Metal Binding Sites and Fluorescent Groups

3_{10}

Fluorescent hydrophobic peptide fragments of emerimicin. Models for the study of peptide aggregation and interactions with lipids and proteins

helical conformations and to initiate the formation of type III \beta bends, stabilised by 4 \rightarrow 1 intramolecular hydrogen bonds. Interest in the stereochemistry of Aib containing peptides, stems from the fact that alamethicin [7,8] and the related polypeptide ionophores antianioebin [9], emmerimicin [10], suzukacillin [11] and trichotoxin [12] contain high proportions of Aib residues. Here, we report the results of an infrared spectroscopic study of synthetic alamethicin fragments and demonstrate the development of a

Ionophore-mediated transmembrane movement of divalent cations in small unilamellar liposomes: An evaluation of the chlortetracycline fluorescence technique and correlations with black lipid membrane studies

3_{10}

Helical conformations of three crystalline pentapeptide fragments of suzukacillin, a membrane channel forming polypeptide

helical structure at the amino-terminus of the antibiotic.