Intramolecular C-N bond activation by a transient boryl anion.

Using a flexible diamido framework, a bulky boron bromide has been prepared as a precusor to a boryl anion with an extremely wide N-B-N angle. Reduction of the compound with lithium metal resulted in intramolecular C-N bond activation and migration of an aryl group onto the boron centre. Reaction of the boron bromide with K[FeCp(CO)] resulted in nucleophilic reactivity of a carbonyl oxygen and the cooperative activation of CO.

Heterobimetallic μ-halocarbyne complexes.

The halocarbyne complexes [M(CX)(CO)(Tp*)] (M = Mo, W; X = Cl, Br; Tp* = hydrotris(dimethylpyrazolyl)borate) react with [AuCl(SMe)], [Pt(η-HCCH)(PPh)] or [Pt(η-nbe)] (nbe = norbornene) to furnish rare examples of μ-halocarbyne complexes [MAu(μ-CX)Cl(CO)(Tp*)], [MPt(μ-CCl)(CO)(PPh)(Tp*)] and [WPt(μ-CCl)(CO)(Tp*)]. The complex [WPt(μ-CCl)(CO)(PPh)(Tp*)] spontaneously rearranges to the μ-carbido complex [WPt(μ-C)Cl(CO)(PPh)(Tp*)] during silica-gel chromatography. One phosphine ligand of [WPt(μ-CCl)(CO)(PPh)(Tp*)] is readily substituted by CO to afford [WPt(μ-CCl)(CO)(PPh)(Tp*)].

Hexokinase-I protection against apoptotic cell death is mediated via interaction with the voltage-dependent anion channel-1: mapping the site of binding.

In brain and tumor cells, the hexokinase isoforms HK-I and HK-II bind to the voltage-dependent anion channel (VDAC) in the outer mitochondrial membrane. We have previously shown that HK-I decreases murine VDAC1 (mVDAC1) channel conductance, inhibits cytochrome c release, and protects against apoptotic cell death. Now, we define mVDAC1 residues, found in two cytoplasmic domains, involved in the interaction with HK-I.

Retina expresses a novel variant of the ryanodine receptor.

Calcium released from intracellular stores via the ryanodine receptor (RyR) mediates a variety of signalling processes. We previously showed that retina expresses the three known types of RyR, but retinal membrane preparations exhibit unique characteristics such as Ca2+-independent [3H]ryanodine-binding and inhibition by caffeine. We have heretofore suggested that the major retinal RyR isoform is novel.

Mapping the ruthenium red-binding site of the voltage-dependent anion channel-1.

We have previously shown that ruthenium red (RuR) binds to the voltage-dependent anion channel (VDAC) in the outer mitochondrial membrane, decreasing channel conductance and protecting against apoptotic cell death. In this report, we define the murine and yeast VDAC1 amino acid residues involved in the interaction with RuR. Binding of RuR to bilayer-reconstituted mVDAC1 and the resulting channel closure was inhibited upon mutation of specific VDAC1 residues.