How soft are biological helices? A measure of axial and lateral force constants in folate quadruplexes by high-pressure X-ray diffraction

Federiconi, Francesco; Mattioni, Michele; Baldassarri, E.; Ortore, María Grazia; Mariani, Paolo

doi:10.1007/s00249-011-0717-0

Cited by 6 publications

(8 citation statements)

References 30 publications

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“…This value corresponds to a unit cell parameter of a = 57.5 Å, where a = 2 d 10 /(3) 1/2 . The radius of a folate tetramer has been estimated to be 15.5 Å in folate solutions. , The d 10 spacing is, hence, consistent with a wall thickness of approximately 18.8 Å between folate stacks. The silica wall must include the amino propyl moiety of APTES, water, and hydrolyzed and unhydrolysed (TEOS) species, because of the early stages of the synthesis.…”

Section: Resultsmentioning

confidence: 73%

Self-Assembly Mechanism of Folate-Templated Mesoporous Silica

et al. 2013

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A method to form ordered mesoporous silica based on the use of folate supramolecular templates has been developed. Evidence based on in situ small-angle X-ray scattering (SAXS), electron microscopy, infrared spectroscopy, and in situ conductivity measurements are used to investigate the organic-inorganic interactions and synthesis mechanism. The behavior of folate molecules in solution differs distinctively from that of surfactants commonly used for the preparation of ordered mesoporous silica phases, notably with the absence of a critical micellar concentration. In situ SAXS studies reveal fluctuations in X-ray scattering intensities consistent with the condensation of the silica precursor surrounding the folate template and the growth of the silica mesostructure in the initial stages. High-angle X-ray diffraction shows that the folate template is well-ordered within the pores even after a few minutes of synthesis. Direct structural data for the self-assembly of folates into chiral tetramers within the pores of mesoporous silica provide evidence for the in register stacking of folate tetramers, resulting in a chiral surface of rotated tetramers, with a rotation angle of 30°. Additionally, the self-assembled folates within pores were capable of adsorbing a considerable amount of CO2 gas through the cavity space of the tetramers. The study demonstrates the validity of using a naturally occurring template to produce relevant and functional mesoporous materials.

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Section: Resultsmentioning

confidence: 73%

Self-Assembly Mechanism of Folate-Templated Mesoporous Silica

et al. 2013

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“…Isolation of detergent-soluble and detergent-insoluble fractions from rat liver basolateral membrane vesicles Detergent-soluble (DS) and insoluble (DI) fractions of liver BLM were prepared essentially as described (Federiconi et al 2011). Briefly, 3 mg of liver BLMVs were centrifuged for 30 min at 100,000g at 4°C and suspended in MES buffer containing 50 mM MES (pH 6.5), 60 mM NaCl, 3 mM EGTA, 5 mM MgCl 2 , 1 % Triton X-100, and 19 complete protease inhibitor cocktail.…”

Section: Binding Of 5-[ 14 C]-methyltetrahydrofolatementioning

confidence: 99%

Decreased activity of folate transporters in lipid rafts resulted in reduced hepatic folate uptake in chronic alcoholism in rats

et al. 2012

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Folic acid is an essential nutrient that is required for one-carbon biosynthetic processes and for methylation of biomolecules. Deficiency of this micronutrient leads to disturbances in normal physiology of cell. Chronic alcoholism is well known to be associated with folate deficiency, which is due in part to folate malabsorption. The present study deals with the regulatory mechanisms of folate uptake in liver during chronic alcoholism. Male Wistar rats were fed 1 g/kg body weight/day ethanol (20 % solution) orally for 3 months, and the molecular mechanisms of folate uptake were studied in liver. The characterization of the folate transport system in liver basolateral membrane (BLM) suggested it to be a carrier mediated and acidic pH dependent, with the major involvement of proton coupled folate transporter and folate binding protein in the uptake. The folate transporters were found to be associated with lipid raft microdomain of liver BLM. Moreover, ethanol ingestion decreased the folate transport by altering the Vmax of folate transport process and downregulated the expression of folate transporters in lipid rafts. The decreased transporter levels were associated with reduced protein and mRNA levels of these transporters in liver. The deranged folate uptake together with reduced folate transporter levels in lipid rafts resulted in reduced folate levels in liver and thereby to its reduced levels in serum of ethanol-fed rats. The chronic ethanol ingestion led to decreased folate uptake in liver, which was associated with the decreased number of transporter molecules in the lipid rafts that can be ascribed to the reduced synthesis of these transporters.

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“…The diluted dispersion contained nanoparticles whose average initial radius was ∼90 nm (Figure ), with a low polydispersity index (PDI) of ∼0.15 (Figure S7a). The nanoparticles were therefore more than an order of magnitude larger than the hexagonal unit cell in NFM-1 or than the length or width of a single folate stack in H 2 O. , They were only slightly larger than the nanoparticles formed when folic acid alone was dispersed in HCl(aq)–THF for 2 h at 60 °C (initial radius ≈ 80 nm, PDI ≈ 0.06; see Figure S8). On the basis of their size and content, the particles are expected to be made up of columns of folic/pteroic acid tetramers intermingled with domains of moderately condensed alkyl- and alkoxysilanes.…”

Section: Resultsmentioning

confidence: 96%

Dispersed Uniform Nanoparticles from a Macroscopic Organosilica Powder

et al. 2018

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A colloidal dispersion of uniform organosilica nanoparticles could be produced via the disassembly of the non-surfactant-templated organosilica powder nanostructured folate material (NFM-1). This unusual reaction pathway was available because the folate and silica-containing moieties in NFM-1 are held together by noncovalent interactions. No precipitation was observed from the colloidal dispersion after a week, though particle growth occurred at a solvent-dependent rate that could be described by the Lifshitz-Slyozov-Wagner equation. An organosilica film that was prepared from the colloidal dispersion adsorbed folate-binding protein from solution but adsorbed ions from a phosphate-buffered saline solution to a larger degree. To our knowledge, this is the first instance of a colloidal dispersion of organosilica nanoparticles being derived from a macroscopic material rather than from molecular precursors.

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How soft are biological helices? A measure of axial and lateral force constants in folate quadruplexes by high-pressure X-ray diffraction

Cited by 6 publications

References 30 publications

Self-Assembly Mechanism of Folate-Templated Mesoporous Silica

Self-Assembly Mechanism of Folate-Templated Mesoporous Silica

Decreased activity of folate transporters in lipid rafts resulted in reduced hepatic folate uptake in chronic alcoholism in rats

Dispersed Uniform Nanoparticles from a Macroscopic Organosilica Powder

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