Photonic immobilization of bsa for nanobiomedical applications: creation of high density microarrays and superparamagnetic bioconjugates

Parracino, Antonietta; Gajula, Gnana Prakash; Gennaro, Ane Kold di; Correia, Manuel; Neves‐Petersen, Maria Teresa; Rafaelsen, Jens; Petersen, Steffen B.

doi:10.1002/bit.23015

Cited by 20 publications

(17 citation statements)

References 65 publications

(73 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In proteins, it can occur directly upon cystine excitation at ~250 nm (wavelength of maximum absorption for dimethylsulfide, model for cystine absorption [ 19 ]), or indirectly upon UV excitation of the side chains of aromatic residues such as tryptophan (Trp, Abs max ~278 nm [ 20 ]), tyrosine (Tyr, Abs max ~275 nm [ 21 ]) and phenylalanine (Abs max ~257 nm [ 20 ]). Reduction of disulphide bridges upon UV excitation of aromatic residues has been shown for proteins such as cutinase and lysozyme [ 22 – 24 ], bovine serum albumin [ 25 , 26 ] prostate specific antigen [ 27 ], alpha-lactalbumin [ 28 ], antibody Fab fragments [ 29 ], and insulin [ 30 ]. Such mechanism is favoured by the spatial proximity between aromatic residues and disulphide bonds, which is a conserved structural feature in proteins [ 31 ].…”

Section: Introductionmentioning

confidence: 99%

Photonic Activation of Plasminogen Induced by Low Dose UVB

et al. 2015

Self Cite

View full text Add to dashboard Cite

Activation of plasminogen to its active form plasmin is essential for several key mechanisms, including the dissolution of blood clots. Activation occurs naturally via enzymatic proteolysis. We report that activation can be achieved with 280 nm light. A 2.6 fold increase in proteolytic activity was observed after 10 min illumination of human plasminogen. Irradiance levels used are in the same order of magnitude of the UVB solar irradiance. Activation is correlated with light induced disruption of disulphide bridges upon UVB excitation of the aromatic residues and with the formation of photochemical products, e.g. dityrosine and N-formylkynurenine. Most of the protein fold is maintained after 10 min illumination since no major changes are observed in the near-UV CD spectrum. Far-UV CD shows loss of secondary structure after illumination (33.4% signal loss at 206 nm). Thermal unfolding CD studies show that plasminogen retains a native like cooperative transition at ~70 ºC after UV-illumination. We propose that UVB activation of plasminogen occurs upon photo-cleavage of a functional allosteric disulphide bond, Cys737-Cys765, located in the catalytic domain and in van der Waals contact with Trp761 (4.3 Å). Such proximity makes its disruption very likely, which may occur upon electron transfer from excited Trp761. Reduction of Cys737-Cys765 will result in likely conformational changes in the catalytic site. Molecular dynamics simulations reveal that reduction of Cys737-Cys765 in plasminogen leads to an increase of the fluctuations of loop 760–765, the S1-entrance frame located close to the active site. These fluctuations affect the range of solvent exposure of the catalytic triad, particularly of Asp646 and Ser74, which acquire an exposure profile similar to the values in plasmin. The presented photonic mechanism of plasminogen activation has the potential to be used in clinical applications, possibly together with other enzymatic treatments for the elimination of blood clots.

show abstract

Section: Introductionmentioning

confidence: 99%

Photonic Activation of Plasminogen Induced by Low Dose UVB

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…An example of extending this analytical concept to investigating NPs capped with common organic ligands is shown in Figure 8 b. For each model colloidal magnetite NP, the dip in M ( T ) is observed at a specific temperature that closely corresponds (within ≤3 K) to the sharp step in thermal decomposition of the capping ligands: poly(vinylpyrrolidone), 29 tetramethylammonium hydroxide, 30 citrate, 31 and poly(acrylic acid). 11 , 12 Observation of a dip in M ( T ) at a characteristic temperature, therefore, can be used to confirm the identities of these common capping ligands.…”

Section: Discussionmentioning

confidence: 99%

High-Temperature Magnetism as a Probe for Structural and Compositional Uniformity in Ligand-Capped Magnetite Nanoparticles

et al. 2014

View full text Add to dashboard Cite

To investigate magnetostructural relationships in colloidal magnetite (Fe3O4) nanoparticles (NPs) at high temperature (300–900 K), we measured the temperature dependence of magnetization (M) of oleate-capped magnetite NPs ca. 20 nm in size. Magnetometry revealed an unusual irreversible high-temperature dependence of M for these NPs, with dip and loop features observed during heating–cooling cycles. Detailed characterizations of as-synthesized and annealed Fe3O4 NPs as well as reference ligand-free Fe3O4 NPs indicate that both types of features in M(T) are related to thermal decomposition of the capping ligands. The ligand decomposition upon the initial heating induces a reduction of Fe3+ to Fe2+ and the associated dip in M, leading to more structurally and compositionally uniform magnetite NPs. Having lost the protective ligands, the NPs continually sinter during subsequent heating cycles, resulting in divergent M curves featuring loops. The increase in M with sintering proceeds not only through elimination of a magnetically dead layer on the particle surface, as a result of a decrease in specific surface area with increasing size, but also through an uncommonly invoked effect resulting from a significant change in Fe3+/Fe2+ ratio with heat treatment. The interpretation of irreversible features in M(T) indicates that reversible M(T) behavior, conversely, can be expected only for ligand-free, structurally and compositionally uniform magnetite NPs, suggesting a general applicability of high-temperature M(T) measurements as an analytical method for probing the structure and composition of magnetic nanomaterials.

show abstract

“…Reduction of SS upon UV excitation of aromatic residues has been shown for proteins such as cutinase and lysozyme [1], [3], [27], bovine serum albumin [28], [29], prostate specific antigen [30], alpha-lactalbumin [4] and antibody Fab fragments [31].…”

Section: Introductionmentioning

confidence: 99%

UV-Light Exposure of Insulin: Pharmaceutical Implications upon Covalent Insulin Dityrosine Dimerization and Disulphide Bond Photolysis

et al. 2012

Self Cite

View full text Add to dashboard Cite

In this work we report the effects of continuous UV-light (276 nm, ∼2.20 W.m−2) excitation of human insulin on its absorption and fluorescence properties, structure and functionality. Continuous UV-excitation of the peptide hormone in solution leads to the progressive formation of tyrosine photo-product dityrosine, formed upon tyrosine radical cross-linkage. Absorbance, fluorescence emission and excitation data confirm dityrosine formation, leading to covalent insulin dimerization. Furthermore, UV-excitation of insulin induces disulphide bridge breakage. Near- and far-UV-CD spectroscopy shows that UV-excitation of insulin induces secondary and tertiary structure losses. In native insulin, the A and B chains are held together by two disulphide bridges. Disruption of either of these bonds is likely to affect insulin’s structure. The UV-light induced structural changes impair its antibody binding capability and in vitro hormonal function. After 1.5 and 3.5 h of 276 nm excitation there is a 33.7% and 62.1% decrease in concentration of insulin recognized by guinea pig anti-insulin antibodies, respectively. Glucose uptake by human skeletal muscle cells decreases 61.7% when the cells are incubated with pre UV-illuminated insulin during 1.5 h. The observations presented in this work highlight the importance of protecting insulin and other drugs from UV-light exposure, which is of outmost relevance to the pharmaceutical industry. Several drug formulations containing insulin in hexameric, dimeric and monomeric forms can be exposed to natural and artificial UV-light during their production, packaging, storage or administration phases. We can estimate that direct long-term exposure of insulin to sunlight and common light sources for indoors lighting and UV-sterilization in industries can be sufficient to induce irreversible changes to human insulin structure. Routine fluorescence and absorption measurements in laboratory experiments may also induce changes in protein structure. Structural damage includes insulin dimerization via dityrosine cross-linking or disulphide bond disruption, which affects the hormone’s structure and bioactivity.

show abstract

Photonic immobilization of bsa for nanobiomedical applications: creation of high density microarrays and superparamagnetic bioconjugates

Cited by 20 publications

References 65 publications

Photonic Activation of Plasminogen Induced by Low Dose UVB

Photonic Activation of Plasminogen Induced by Low Dose UVB

High-Temperature Magnetism as a Probe for Structural and Compositional Uniformity in Ligand-Capped Magnetite Nanoparticles

UV-Light Exposure of Insulin: Pharmaceutical Implications upon Covalent Insulin Dityrosine Dimerization and Disulphide Bond Photolysis

Contact Info

Product

Resources

About