Recognition and sensing of low-epitope targets via ternary complexes with oligonucleotides and synthetic receptors.

Oligonucleotide-based receptors or aptamers can interact with small molecules, but the ability to achieve high-affinity and specificity of these interactions depends strongly on functional groups or epitopes displayed by the binding targets. Some classes of targets are particularly challenging: for example, monosaccharides have scarce functionalities and no aptamers have been reported to recognize, let alone distinguish from each other, glucose and other hexoses. Here we report aptamers that differentiate low-epitope targets such as glucose, fructose or galactose by forming ternary complexes with high-epitope organic receptors for monosaccharides.

Autonomous molecular cascades for evaluation of cell surfaces.

Molecular automata are mixtures of molecules that undergo precisely defined structural changes in response to sequential interactions with inputs. Previously studied nucleic acid-based automata include game-playing molecular devices (MAYA automata) and finite-state automata for the analysis of nucleic acids, with the latter inspiring circuits for the analysis of RNA species inside cells. Here, we describe automata based on strand-displacement cascades directed by antibodies that can analyse cells by using their surface markers as inputs.

Binding of phosphoinositide-specific phospholipase C-zeta (PLC-zeta) to phospholipid membranes: potential role of an unstructured cluster of basic residues.

Phospholipase C-zeta (PLC-zeta) is a sperm-specific enzyme that initiates the Ca2+ oscillations in mammalian eggs that activate embryo development. It shares considerable sequence homology with PLC-delta1, but lacks the PH domain that anchors PLC-delta1 to phosphatidylinositol 4,5-bisphosphate, PIP2. Thus it is unclear how PLC-zeta interacts with membranes.

Structure of the membrane reconstituted transmembrane-juxtamembrane peptide EGFR(622-660) and its interaction with Ca2+/calmodulin.

The transmembrane (TM) and juxtamembrane (JM) regions of the epidermal growth factor receptor (EGFR) couple ligand binding in the extracellular domain to activation of the kinase domain. Solid-state NMR and polarized FTIR measurements of peptides corresponding to the TM plus JM regions of EGFR (residues 622-660) reconstituted in model phospholipid membranes are presented to address the role of the short cytoplasmic JM sequence (residues 645-660) in regulating EGFR activity. We show that the TM domain is helical with a transition to non-helical structure at the TM-JM boundary.