The supramolecular chemistry of gold and l-cysteine: Formation of photoluminescent, orange-emitting assemblies with multilayer structure

The protein mediated approach is a common method for the synthesis of photoluminescent gold quantum clusters (GQCs), where proteins, acting as reducing and stabilizing agents, react with gold salts through cysteine residues. For the better understanding of the phenomenon, the aqueous phase reaction of HAuCl_4 and L-cysteine has been investigated at the supramolecular level by various experimental techniques and molecular mechanics simulations. We have observed the formation of a novel photoluminescent product, (AuCys)_n^β, which shows emission in the orange region of the spectrum. Small- and wide-angle X-ray scattering (SWAXS) measurements have revealed the presence of nanosized lamellae, which have an internal multilayer superlattice structure with a characteristic periodic distance of 1.3 nm. Based on the results, the layers are built up by zigzag shaped (AuCys)_n polymer chains connected through aurophilic bonds. The aurophilic network is stabilized via salt bridges and hydrogen bonds, which are also responsible for the interlayer interactions. Here, the evolution of the multilayer structure has been monitored by the combined application of photoluminescence spectroscopy and time-resolved SAXS. It has been concluded that there is a strong correlation between the emission and the scattering intensity, which suggests that the two- and three-dimensional aggregation of the building blocks to form sheets and multilayers are simultaneous processes. Furthermore, we have revealed that the formation and behavior of (AuCys)_n^β show significant differences to that of Au-L-glutathione compounds desrcibed earlier despite the similarity of L-cysteine and L-glutathione. These results evidence that L-cysteine and gold species form building blocks that can be applied expansively in supramolecular and cluster chemistry

GLUT10-Lacking in Arterial Tortuosity Syndrome-Is Localized to the Endoplasmic Reticulum of Human Fibroblasts.

GLUT10 belongs to a family of transporters that catalyze the uptake of sugars/polyols by facilitated diffusion. Loss-of-function mutations in the SLC2A10 gene encoding GLUT10 are responsible for arterial tortuosity syndrome (ATS). Since subcellular distribution of the transporter is dubious, we aimed to clarify the localization of GLUT10. In silico GLUT10 localization prediction suggested its presence in the endoplasmic reticulum (ER). Immunoblotting showed the presence of GLUT10 protein in the microsomal, but not in mitochondrial fractions of human fibroblasts and liver tissue. An even cytosolic distribution with an intense perinuclear decoration of GLUT10 was demonstrated by immunofluorescence in human fibroblasts, whilst mitochondrial markers revealed a fully different decoration pattern. GLUT10 decoration was fully absent in fibroblasts from three ATS patients. Expression of exogenous, tagged GLUT10 in fibroblasts from an ATS patient revealed a strict co-localization with the ER marker protein disulfide isomerase (PDI). The results demonstrate that GLUT10 is present in the ER

Glucose transporter type 10—lacking in arterial tortuosity syndrome—facilitates dehydroascorbic acid transport

Loss-of-function mutations in the gene encoding GLUT10 are responsible for arterial tortuosity syndrome (ATS), a rare connective tissue disorder. In this study GLUT10-mediated dehydroascorbic acid (DAA) transport was investigated, supposing its involvement in the pathomechanism. GLUT10 protein produced by in vitro translation and incorporated into liposomes efficiently transported DAA. Silencing of GLUT10 decreased DAA transport in immortalized human fibroblasts whose plasma membrane was selectively permeabilized. Similarly, the transport of DAA through endomembranes was markedly reduced in fibroblasts from ATS patients. Re-expression of GLUT10 in patients’ fibroblasts restored DAA transport activity. The present results demonstrate that GLUT10 is a DAA transporter and DAA transport is diminished in the endomembranes of fibroblasts from ATS patients

Molecular and clinical analysis of patients with classic and Duarte galactosemia in western Hungary

BACKGROUND: Classic galactosemia is an autosomal recessively inherited disorder caused by deficient activity of the enzyme galactose-1-phosphate uridyltransferase. The disorder can be detected by newborn screening and in Hungary the national screening program was launched in 1976 with two screening centers. The aim of this study was the molecular characterization of the genotypes and analysis of genotype-phenotype correlation among patients with classic or variant galactosemia. PATIENTS AND METHODS: DNA samples from 40 patients were analyzed by polymerase chain reaction followed by direct sequencing. RESULTS: 16 different sequence variations were identified, including two novel missense mutations (p.S297P, p.E146D). The two most common mutations were p. Q188R and p.K285N with allele frequencies of 45% and 31.2%, respectively. Clinical data were evaluated with respect to the genotypes found. CONCLUSIONS: The most serious clinical phenotypes in our population were associated with mutations p. Q188R, p.K285N, p.X380R, p.S297P, p.M142K, p.R.204X, p.Q169K and p.R407P, but manifestations depend on other genetic and environmental factors

Subcellular compartmentation of ascorbate and its variation in disease states.

Beyond its general role as antioxidant, specific functions of ascorbate are compartmentalized within the eukaryotic cell. The list of organelle-specific functions of ascorbate has been recently expanded with the epigenetic role exerted as a cofactor for DNA and histone demethylases in the nucleus. Compartmentation necessitates the transport through intracellular membranes; members of the GLUT family and sodium-vitamin C cotransporters mediate the permeation of dehydroascorbic acid and ascorbate, respectively. Recent observations show that increased consumption and/or hindered entrance of ascorbate in/to a compartment results in pathological alterations partially resembling to scurvy, thus diseases of ascorbate compartmentation can exist. The review focuses on the reactions and transporters that can modulate ascorbate concentration and redox state in three compartments: endoplasmic reticulum, mitochondria and nucleus. By introducing the relevant experimental and clinical findings we make an attempt to coin the term of ascorbate compartmentation disease