Showing papers on "Polyamine binding published in 2002"
TL;DR: It is suggested that rhynchophylline and isorhynchopylline act as noncompetitive antagonists of the NMDA receptor and that this property may contribute to the neuroprotective and anticonvulsant activity of the Uncaira species plant extracts.
129 citations
TL;DR: It is reported that micromolar concentrations of the polyamines, spermidine(4+) and spermine(3+), can substitute for divalent cations in modulating 14-3-3 action and proposed that binding of polyamines to 14- 3-3s could be involved in their regulation of plant growth and development.
Abstract: *Summary Binding of 14-3-3 proteins to nitrate reductase phosphorylated on Ser543 (phospho-NR) inhibits activity and is responsible for the inactivation of nitrate reduction that occurs in darkened leaves. The 14-3-3dependent inactivation of phospho-NR is known to require millimolar concentrations of a divalent cation such as Mg2+ at pH 7.5. We now report that micromolar concentrations of the polyamines, spermidine 4+ and spermine 3+ , can substitute for divalent cations in modulating 14-3-3 action. Effectiveness of the polyamines decreased with a decrease of polycation charge: spermine 4+ > spermidine 3+ >>> cadavarine 2+ » putrescine 2+ » agmatine 2+ » N 1 -acetylspermidine 2+ , indicating that two primary and at least one secondary amine group were required. C-terminal truncations of GF14w, which encodes the Arabidopsis 14-3-3 isoform w, indicated that loop 8 (residues 208‐219) is the likely cationbinding site. Directed mutagenesis of loop 8, which contains the EF hand-like region identified in earlier studies, was performed to test the role of specific amino acid residues in cation binding. The E208A mutant resulted in a largely divalent cation-independent inhibition of phospho-NR activity, whereas the D219A mutant was fully Mg2+ -dependent but had decreased affinity for the cation. Mutations and Cterminal truncations that affected the Mg 2+ dependence of phospho-NR inactivation had similar effects on polyamine dependence. The results implicate loop 8 as the site of divalent cation and polyamine binding, and suggest that activation of 14-3-3s occurs, at least in part, by neutralization of negative charges associated with acidic residues in the loop. We propose that binding of polyamines to 14-3-3s could be involved in their regulation of plant growth and development.
114 citations
TL;DR: Saturation binding studies reveal that huperzine A exerts a negative allosteric modulation on the MK-801 binding site within the NMDA receptor-channel, acting at one of the polyamine binding sites.
22 citations
TL;DR: The structure of this PA(222) molecule presents the previously reported zig‐zag type conformation, and comparison of this structure with other polyamine–DNA cocrystals reveals structural themes and differences that may relate to the length of the polyamine.
17 citations
Patent•
24 Oct 2002
TL;DR: In this paper, a method for synthesizing polyamine-conjugated polyamine combinatorial libraries and methods for screening for polyamine binding molecules in biological samples is presented.
Abstract: The invention is directed to resin-conjugated polyamine combinatorial libraries and methods for making and using them, e.g., methods for screening for polyamine binding molecules in biological samples. The invention provides protected benzophenone-substituted resins, and methods for their synthesis. The invention provides hydroxy-triarylmethane-conjugated resins, and methods for their synthesis. The invention provides chlorotriarylmethane resins, and methods for their synthesis. The invention provides resin-conjugated peptide libraries, and methods for their synthesis.
3 citations