A membrane-spanning heptad repeat motif mediates interaction between transmembrane segments. This motif was randomized with three different sets of mostly hydrophobic residues in the context of POSSYCCAT, a modified ToxR transcription activator system. The resulting combinatorial libraries were subjected to different levels of selective pressure to obtain groups of transmembrane segments that a...

Inspired by the key role of super-helical motifs in molecular self-organization, several tandem heptad repeat peptides were used as building blocks to form well-ordered supramolecular nano-assemblies. However, the need for stable helical structures limits the length of the smallest described units to three heptad repeats. Here we describe the first-ever self-assembling single heptad repeat modu...

Fusion proteins of enveloped viruses categorized as class I are typified by two distinct heptad repeat domains within the transmembrane subunit. These repeats are important structural elements that assemble into the six-helix bundles characteristic of the fusion-activated envelope trimer. Peptides derived from these domains can be potent and specific inhibitors of membrane fusion and virus infe...

UNLABELLED The HIV-1 envelope glycoprotein (Env) is a trimer of gp120-gp41 heterodimers and is essential for viral entry. The gp41 subunit in native, prefusion trimeric Env exists in a metastable conformation and attains a stable six-helix bundle (6-HB) conformation comprised of a trimer of N-heptad repeat (NHR) and C-heptad repeat (CHR) heterodimers, that drives the fusion of viral and cellula...

The stability and compatibility of designed coiled coil peptides towards the selective incorporation of γ(4)-amino acids at the hydrophobic positions of the heptad repeat are studied. Investigations reveal that the low thermal denaturation temperature of γ(4)-residue mutated coiled coils can be utilized as a mild hyperthermia trigger in liposomes.

Recent studies showed that p34(SEI-1), also known as TRIP-Br1 or SEI-1, plays a dual role in the regulation of cell-cycle progression. It exhibits the transactivation activity and regulates a number of genes required for G1/S transition, while it also binds and activates cyclin-dependent kinase 4 (CDK4) independent of the inhibitory activity of p16. The goals of this paper are to further dissec...