Circular dichroism spectra of homocysteinylated proteins.

<p>Far-UV CD spectra (at 37°C) of lysozyme (A), RNase-A (B) and α-LA (C) modified with varying concentrations of HTL ranging from 0–1000 µM, at pH 7.4 (left panel). Near-UV CD spectra of lysozyme (D), RNase-A (E) and α-LA (F) modified with varying concentrations of HTL ranging from 0–1000 µM, at pH 7.4 (right panel).</p

Hydrodynamic diameter of HTL-treated α-LA samples.

<p>Solution containing 2 mg ml⁻¹ of α-LA was withdrawn from the reaction mixtures and analysed without any dilution. All measurements were performed at 37°C. The values reported represent the mean ± SD calculated from three independent experiments.</p><p>Hydrodynamic diameter of HTL-treated α-LA samples.</p

Effect of homocysteine thiolactone (HTL) on the extrinsic fluorescence of the native state of proteins.

<p>ANS binding study (A) cyt-c (at 18 hours), (B) α-LA (at 4 hours) and (C) lysozyme (at 24 hours) modified with different concentrations of HTL. Excitation wavelength of 360 nm was used and emissions were recorded at the wavelength range of 400–600 nm.</p

Homocysteine thiolactone (HTL) induced aggregation study of cyt-c and α-LA.

<p>Turbidometric study of (A) cyt-c (at 500 nm) and (B) α-LA (at 400 nm) modified with different concentrations of HTL at 24 hours.</p

Melting temperature (<i>T</i>_m) of lysozyme and RNase-A on being treated overnight with HTL at 37°C^a.

a<p>Errors in <i>T</i>_m are .2–1%. Measurements were repeated at least three times.</p><p>Melting temperature (<i>T</i>_m) of lysozyme and RNase-A on being treated overnight with HTL at 37°C^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116386#nt106" target="_blank">a</a>}.</p

Hydrodynamic diameter of cyt-c, α-LA and lysozyme^*.

<p>*Experimental error in hydrodynamic diameter measurement is in the range of 7–9%.</p><p>Hydrodynamic diameter of cyt-c, α-LA and lysozyme^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113566#nt101" target="_blank">*</a>}.</p

Synthesis of Aminophenanthrenes and Benzoquinolines via Hauser–Kraus Annulation of Sulfonyl Phthalide with Rauhut–Currier Adducts of Nitroalkenes

The Hauser–Kraus reaction of sulfonyl phthalide with nitroalkene derivatives provides access to aminophenanthrenes, including phenanthrene-substituted amino acids and benzoquinolines. The intermediate quinones bearing a key ketoalkyl moiety undergoes facile intramolecular enamine cyclization. Interestingly, enamines derived from primary and secondary amines undergo cyclization via C-centered nucleophilic attack to provide aminophenanthrenes, whereas those derived from ammonia undergo cyclization via N-centered nucleophilic attack leading to benzoquinolines. A one-pot protocol for the direct transformation of phthalides and nitroalkene derivatives to aminophenanthrenes and benzoquinolines has also been developed

Effect of homocysteine thiolactone (HTL) on the intrinsic fluorescence of the native state of proteins.

<p>Intrinsic fluorescence spectra of (A) cyt-c (at 18 hours), (B) α-LA (at 4 hours) and (C) lysozyme (at 24 hours) modified with different concentrations of HTL. Unfolded state control (7.0 M GdmCl) have also been shown for each protein. Inset in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0113566#pone-0113566-g004" target="_blank">Figure 4</a> (A) shows the enlarged view of the native state emission spectra of cyt-c. Excitation wavelength of 295 nm was used for all the three proteins and emissions were recorded at the wavelength range of 300–500 nm.</p

ANS binding assay (left panel) of lysozyme (A), RNase-A (B) and α-LA (C) treated overnight at 37°C with varying concentrations of HTL.

<p>Right panels depict λ_max as a function of HTL concentrations of lysozyme (D), RNase-A (E) and α-LA (F). To maintain clarity, only the representative curves of free dyes (dotted lines), control unmodified protein (solid lines) and protein modified with 1000 µM HTL (dashed lines) are shown.</p

Effect of homocysteine thiolactone (HTL) on the hydrodynamic diameter of the native state of proteins.

<p>Percent increase in hydrodynamic diameter of (A) cyt-c (at 18 hours) and (B) α-LA (at 4 hours) and (C) lysozyme (at 24 hours) after modification with different concentrations of HTL.</p