The single crystals of tetrameric [Me3Sn(PhN2O2)]4 (1) supramolecule demethylates into single crystals of [Me2Sn(PhN2O2)2]2 dimer (2) and volatile Me4Sn, as a result of a crystal-to-crystal supramolecular structural transformation, which occurs upon heating and it is accompanied by a significant change of the molecular and crystal structures.

mAbs capable of disabling heterodimeric kinase complexes of the epidermal growth factor receptor (EGFR) and human EGFR type 2/neu have therapeutic relevance to various human cancers. In this study, we demonstrate that in addition to the dimer, EGFR and human EGFR type 2 can associate as homo- and heterotetramers. EGF-induced phosphorylation of the tetramers was significantly lower than that of ...

Homer is a crucial postsynaptic scaffolding protein involved in both maintenance and activity-induced plasticity of the synapse. However, its quaternary structure has yet to be determined. We conducted a series of biophysical experiments that provide the first evidence that Homer forms a tetramer via its coiled-coil domain, in which all subunits are aligned in parallel orientation. To test the ...

The time-dependent loss of enzymic activity and tetrameric structure of chicken liver pyruvate carboxylase (EC 6.4.1.1) after dilution below 2 units/ml was apparently monophasic and first-order. When examined over a range of initial enzyme concentrations, both activity and tetrameric structure decayed to equilibrium levels which were dependent on the initial concentration. The observed rate con...

LysR-type transcription regulators (LTTRs) comprise one of the largest families transcriptional in bacteria. They are typically homo-tetrameric proteins and interact with promoter DNA ~ 50–60 bp. Earlier biochemical studies have suggested that LTTR binding to bends and, upon inducer binding, bend angle is reduced through a quaternary structure change tetrameric LTTR, leading activation transcri...

In vivo imaging of avb3 expression has important diagnostic and therapeutic applications. Multimeric cyclic RGD peptides are capable of improving the integrin avb3–binding affinity due to the polyvalency effect. Here we report an example of 18F-labeled tetrameric RGD peptide for PET of avb3 expression in both xenograft and spontaneous tumor models. Methods: The tetrameric RGD peptide EfE[c(RGDy...