Polyamine block

Brissault B, Kichler A, Leborgne C et al (2006) Synthesis, characterization, and gene transfer application of poly(ethylene glycol-b-ethylenimine) with high molar mass polyamine block. Biomacromolecules 7 2863-2870... 

Preliminary results indicate the possibility of preparing ABA block copolymers containing polyacetal (as a middle block) and polyamine blocks 121). When N-t-butylaziridine or 2-phenyl-2-oxazoline are added to a solution of living polyDXP, further polymerization ensues and the products have considerably higher molecular weights than the original polyDXP. NMR analysis confirmed the block character of the product. 

Polyamine Block of Inwardly Rectifying Potassium (Kir) Channels... 

Characteristics of Polyamine Block 18.2.1 Steepness of Voltage-Dependent Block... 

Fig. 18.2 Atomic resolution structure of Kir2.2. Coordinates used were reported by Hansen et al., (2011). Two subunits have been removed to more clearly depict the central pore axis that forms the permeation pathway. The rectification controller residue, and cytoplasmic residues important for polyamine block, are highlighted as spheres...

Fig. 183 Coupled movement of blockers and ions in Kir channel pores. Each image is a schematic of a Kir channel, depicting the progressive movement of spermine as it interacts with the cytoplasmic domain of the channel and migrates toward its stable binding site. As the blocker moves toward the deep binding site, multiple ions are displaced through the transmembrane field, generating the steep voltage dependence associated with polyamine block...

Inner Cavity Residues That Control Polyamine Block... 

Polyamine block of Kir channels is an essential physiological mechanism of ion channel regulation that is distinct from the more commonly studied roles of polyamines in cell growth and proliferation. Intracellular polyamines enter the Kir channel pore at depolarized voltages, causing preferential blockade of outward K currents and allowing cellular electrical excitation to proceed. Recently identified mutations of the Kir2.1 channel cause disruption of polyamine block and are linked to cardiac arrhythmias. 

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