322,945 research outputs found
SERS-based nanobiosensing for ultrasensitive detection of the p53 tumor suppressor
No full textFabio Domenici, Anna Rita Bizzarri, Salvatore Cannistraro Biophysics and Nanoscience Centre, Faculty of Science, Università della Tuscia, Viterbo, Italy Background: One of the main challenges in biomedicine is improvement of detection sensitivity to achieve tumor marker recognition at a very low concentration when the disease is not significantly advanced. A pivotal role in cancer defense is played by the p53 tumor suppressor, therefore its detection with high sensitivity may contribute considerably to early diagnosis of cancer. In this work, we present a new analytical method based on surface-enhanced Raman spectroscopy which could significantly increase the sensitivity of traditional bioaffinity techniques. p53 molecules were anchored to gold nanoparticles by means of the bifunctional linker 4-aminothiophenol (4-ATP). The characteristic vibrational bands of the p53-4-ATP nanoparticle system were then used to identify the p53 molecules when they were captured by a recognition substrate comprising a monolayer of azurin in molecules possessing significant affinity for this tumor suppressor. The Raman signal enhancement achieved by 4-ATP-mediated crosslinking of p53 to 50 nm gold nanoparticles enabled detect of this protein at a concentration down to 5 × 10-13 M. Keywords: surface-enhanced Raman spectroscopy, p53, ultrasensitive detection, atomic force microscop
Monte Carlo Simulation of the Electron Paramagnetic Resonance Spectrum Displayed by Ceruloplasmin at 77 K
No full textField Swept and Frequency Swept EPR Spectra for Spin 1/2: Computer Simulation in the Presence of and Strain
No full textInfluence of paramagnetic ions bound to human serum albumin on water 1HNMR relaxation times.
No full textThe extent to which various paramagnetic ions (Cu2+, Mn2+ and Gd3+) free and
bound to human serum albumin alter the water proton relaxation times at two
frequencies has been investigated. NMR relaxation parameters, T1 and T2, were
measured at 5 and 10 MHz using a saturation recovery (90 degrees-tau-90 degrees)
and a spin-echo (90 degrees-tau-180 degrees) sequence respectively. We found that
all three ions enhance their effectiveness in inducing water proton magnetic
relaxation when they are bound to human serum albumin and that Gd3+ is the most
effective in pure water and Mn2+ in the presence of the protein. Cu2+ has a
smaller effect, but it presents an interesting behaviour correlated with the
existence of two different binding sites, which is also confirmed by electronic
paramagnetic resonance spectra. The results indicate the potential usefulness of
large molecular paramagnetic complexes as contrast agents in NMR Imaging
Gd3+-TPPS: a potential paramagnetic contrast agent in NMR imaging
No full textA water soluble paramagnetic metalloporphyrin containing Gd3+ as metal ion has
been investigated by low resolution 1H NMR to evaluate the extent to which it
alters the water proton relaxation times. The obtained results seem to indicate a
potential usefulness of this complex as a paramagnetic contrast agent for NMR
Imaging
ELECTRONIC PARAMAGNETIC RESONANCE AND OPTICAL SPECTROSCOPIC STUDY OF THE HEME-HUMAN SERUM ALBUMIN COMPLEX.
No full textHydration and protein dynamics: an ESR and ST-ESR spin labelling study of human serum albumin
No full textHuman serum albumin has been studied at low hydration level by the ESR spin labelling technique, under the assumption that a covalently bound spin-label is a reporter of the protein internal dynamics. At room temperature, the presence of a double component signal allowed us to monitor the influence of increasing hydration level on internal protein dynamics as well as on the superficial water dynamics. The ESR results have shown that the first 20 g of water per 100 g of protein activate the internal protein dynamics and that superficial water dynamics starts at higher hydration values. ESR experiments at low temperature have shown that at −160°C ≲T≲−80°C, the label experiences an increasing environmental polarity with increasing temperature in the samples with hydration values higher than about 20 g of water per 100 g of protein. The results are discussed in connection with both conformational substates of the protein and hydration water dynamics
Small angle neutron scattering and spin labeling of human ceruloplasmin
No full textSmall angle neutron scattering evidence of intermolecular correlations between cerulo plasmin units in anaqueous medium is provided. By the same technique, the radius of gyration of the globular biomolecule has been calculated to be 33 ± 3 Å. This value was found to agree very well with that measured by the authors with a spin labeling approach
Simulation of EPR Spectra of Cu Complexes with Statistical Distribution of the --Factor and Hyperfine Splitting
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