Expression of voltage-gated K channel, shaker-related subfamily, member 5 (KCNA5) underlies the human atrial ultra-rapid delayed rectifier K current (I(Kur)). The KCNA5 polymorphism resulting in P532L in the C terminus generates I(Kur) that is indistinguishable from wild type at baseline but strikingly resistant to drug block. In the present study, truncating the C terminus of KCNA5 generated a...

Five highly homologous epidermal growth factor receptor ligands were studied by mass spectral analysis, hydrogen/deuterium (H/D) exchange via attenuated total reflectance Fourier transform-infrared spectroscopy, and two-dimensional correlation analysis. These studies were performed to determine the order of events during the exchange process, the extent of H/D exchange, and associated kinetics ...

BACKGROUND Ribosomal protein S15 is a primary RNA-binding protein that binds to the central domain of 16S rRNA. S15 also regulates its own synthesis by binding to its own mRNA. The binding sites for S15 on both mRNA and rRNA have been narrowed down to less than a hundred nucleotides each, making the protein an attractive candidate for the study of protein-RNA interactions. RESULTS The crystal...

Synthetic heme-binding four-alpha-helix bundles show promise as working model systems, maquettes, for understanding heme cofactor-protein assembly and function in oxidoreductases. Despite successful inclusion of several key functional elements of natural proteins into a family of heme protein maquettes, the lack of 3D structures, due principally to conformational heterogeneity, has prevented th...

Using a combination of explicit solvent atomistic simulation and continuum theory, here we study the lateral deformation mechanics of three distinct protein structures: an amyloid fibril, a beta helix, and an alpha helix. We find that the two β-sheet rich structures - amyloid fibril and beta helix, with persistence lengths on the order of μm - are well described by continuum mechanical theory, ...

Vpu is an 81-residue membrane protein encoded by the HIV-1 genome. NMR experiments show that the protein folds into two distinct domains, a transmembrane hydrophobic helix and a cytoplasmic domain with two in-plane amphipathic alpha-helices separated by a linker region. Resonances in one-dimensional solid-state NMR spectra of uniformly (15)N labeled Vpu are clearly segregated into two bands at ...

Apolipoprotein (apo) E, via its receptor binding domain contained in residues 140-150, mediates hepatic and peripheral tissue binding of cholesterol-rich lipoproteins. Previously, we reported that a synthetic peptide representing a linear tandem repeat of amino acids 141-155, the 141-155 dimer, binds the low density lipoprotein (LDL) receptor. To define the structural features essential for LDL...

Many peptides and proteins that act at lipid--water interfaces assume a unique amphiphilic secondary structure which is induced by the anisotropy of the interface. By using synthetic peptides in which these inducible amphiphilic structures have been optimized, one can show that the amphiphilic alpha helix is a functional determinant of representative apolipoproteins, peptide toxins, and peptide...

We study atomic models of the thermodynamics of the structural transition of peptides that form alpha-helices. The effect of sequence variation on alpha-helix formation for alanine-rich peptides, Ac-Ala21-methyl amide (A21) and Ac-A5 (AAARA)3A-methyl amide (Fs peptide), is investigated by atomic simulation studies of the thermodynamics of the helix-coil transition in explicit water. The simulat...

The de novo design and structural characterization of an alpha-helical hairpin peptide (alpha-helix/turn/alpha-helix, alpha t alpha) are reported. The peptide is intended to provide a model system for the study of the interactions of secondary structural elements during protein folding. Both the diffusion-collision and framework models of protein folding envision that the earliest intermediates...