Bombolitin I and III (BI and BIII) are small amphiphilic peptides isolated from bumblebee venom. Although they exist in predominately nonhelical conformations in dilute aqueous solutions, we demonstrate, using UV Raman spectroscopy, that they become predominately alpha-helical in solution at pH > 10, in high ionic strength solutions, and in the presence of trifluoroethanol (TFE) and dodecylphos...

Escherichia coli NikR, a repressor with homologs in other bacteria and archaea, was identified as a potential new member of the ribbon-helix-helix (beta-alpha-alpha) family of transcription factors in profile based sequence searches and in structure prediction experiments. Biophysical and biochemical characterization of the N-terminal domain of NikR show that it has many features expected of a ...

Apolipoprotein (apo) A-I is thought to undergo a conformational change during lipid association that results in the transition of random coil to alpha-helix. Using a series of deletion mutants lacking different regions along the molecule, we examined the contribution of alpha-helix formation in apoA-I to the binding to egg phosphatidylcholine (PC) small unilamellar vesicles (SUV). Binding isoth...

The shortest helices (three-length 3(10) and four-length alpha), most abundant among helices of different lengths, have been analyzed from a database of protein structures. A characteristic feature of three-length 3(10)-helices is the shifted backbone conformation for the C-terminal residue (phi,psi angles: -95 degrees,0 degrees ), compared to the rest of the helix (-62 degrees,-24 degrees ). T...

Gene-specific targeting of the Sin3 corepressor complex by DNA-bound repressors is an important mechanism of gene silencing in eukaryotes. The Sin3 corepressor specifically associates with a diverse group of transcriptional repressors, including members of the Mad family, that play crucial roles in development. The NMR structure of the complex formed by the PAH2 domain of mammalian Sin3A with t...

Aggregation and fibrillation of alpha-synuclein bound to membranes are believed to be involved in Parkinson's and other neurodegenerative diseases. On SDS micelles, the N-terminus of alpha-synuclein forms two curved helices linked by a short loop. However, its structure on lipid bilayers has not been experimentally resolved. Using MD simulations with an implicit membrane model we show here that...