Transient Kinetics Reveal Mechanism and Voltage Dependence of Inhibitor and Substrate Binding to Glutamate Transporters.

Plasma-membrane glutamate transporters of the excitatory amino acid transporter (EAAT) family are important for maintaining a low glutamate concentration in the extracellular space of the mammalian brain. Glutamate is believed to be transported in its negatively charged form and energetically driven by the cotransport of three sodium ions, at least two of which are bound within the dielectric of the membrane. It was hypothesized that binding of substrates and competitive inhibitors is also electrogenic because the binding site is located near the center of the membrane.

Sequence selective recognition of double-stranded RNA at physiologically relevant conditions using PNA-peptide conjugates.

Conjugation of short peptide nucleic acids (PNA) with tetralysine peptides strongly enhanced triple helical binding to RNA at physiologically relevant conditions. The PNA hexamers and heptamers carrying cationic nucleobase and tetralysine modifications displayed high binding affinity for complementary double-stranded RNA without compromising sequence selectivity. The PNA-peptide conjugates had unique preference for binding double-stranded RNA, while having little, if any, affinity for double-stranded DNA.