The residual activities of the four Ser102 mutants as compared to the wild-type SmIDH.

<p>The residual activities of the four Ser102 mutants as compared to the wild-type SmIDH.</p

Enzyme purity, western blot and molecular mass analysis of SmIDH.

<p>(A) SDS-PAGE analysis of the expression and purification of SmIDH. Analysis was performed on 12% polyacrylamide gel. M, protein markers; lane 1, crude extracts of cells harboring pWT grown in MD medium without glutamate. lane 2, purified protein. (B) Western blot analysis using anti-6×His antibody as probe. (C) Molecular mass determination by gel filtration chromatography. The flow rate was 0.5 ml/min and the proteins in the fractions were monitored at 280 nm. Inside is the standard curve for molecular mass. SmIDH was represented as a dark circle (•). Standard proteins were represented by open circles (○): 1, Ovalbumin (44 kDa); 2, Conalbumin (75 kDa); 3, Aldolase (158 kDa); 4, Ferritin (440 kDa); 5, Thyroglobulin (669 kDa). <i>V</i>_e of SmIDH is 14.4 ml.</p

Circular diochroism (CD) spectra of the wild-type SmIDH and four mutants, S102T, S102G, S102A and S102Y.

<p>The CD was measured and the molar ellipticity was calculated as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058918#s2" target="_blank">Materials and methods</a>.</p

Construction of SmIDH mutants.

a<p>Dashes indicate the same amino acid residues as SmIDH.</p>b<p>Only sense primers are shown. Underlines indicate mutated regions.</p

Kinetic analysis of the recombinant SmIDH.

<p>The kinetic parameters of the recombinant SmIDH were determined by measuring its enzyme activity at various isocitrate or NAD⁺ concentrations with the other substrate at saturating concentrations. Enzymatic activity was assessed by monitoring the increase of NADH. The SmIDH <i>K</i>_m for NAD⁺ (A) and isocitrate (B) were calculated as 154 μM and 75 μM, respectively, by averaging values from triplicate experiments.</p

Structure-based protein sequence alignment of SmIDH with other dimeric IDHs.

<p>High-resolution crystal structures of <i>E. coli</i> NADP-IDH (EcIDH, 9ICD), <i>B. subtilis</i> NADP-IDH (BsIDH, 1HQS) and <i>A. thiooxidans</i> NAD-IDH (AtIDH, 2D4V) were downloaded from the PDB database. SmIDH structure was generated using the SWISS-MODEL modeling server, using AtIDH as a template structure. Invariant residues are highlighted by shaded blue boxes and conserved residues by open blue boxes. The conserved residues involved in the cofactor binding (▴) and substrate binding (*) are indicated. The phosphorylation site was represented by ★. The phosphorylation loop and the insert region were highlighted by shaded orange boxes. The figure was made with ESPript 2.2 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058918#pone.0058918-Gouet1" target="_blank">[36]</a>.</p

Effects of metal ions on the activity of recombinant SmIDH ^a.

a<p>The values indicate the means of at least three independent measurements.</p

Application of Fe/Activated Carbon Catalysts in the Hydroxylation of Phenol to Dihydroxybenzenes

A series of Fe/activated carbon catalysts were prepared by impregnation of activated carbon with aqueous solution of ferric nitrate and employed in phenol hydroxylation to dihydroxybenzenes using hydrogen peroxide as oxidant. The samples were characterized by thermal analysis, inductively coupled plasma atomic emission spectrometry (ICP-AES), N₂-adsorption, temperature-programmed oxidation mass spectrometry (TPO-MS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Part of the ferric (Fe­(III)) species was reduced to ferrous (Fe­(II)) species forming Fe₃O₄ when the Fe/activated carbon catalyst was heated at 400 °C for 3 h in air. Fe₃O₄ highly dispersed on activated carbon was found to be the active phase for the target reaction. The appearance of ferrous (Fe­(II)) species greatly improved the catalytic activity. A phenol conversion of 41.3% and a yield of 36.0% to dihydroxybenzenes were obtained under the following optimal reaction conditions: catalyst amount, 0.1 g; reaction temperature, 30 °C; molar ratio of phenol/H₂O₂, 10.6/9.8; reaction time, 1 h

Bioinspired Fabrication of Hierarchical-Structured Superhydrophobic Surfaces To Understand Droplet Bouncing Dynamics for Enhancing Water Repellency

Dynamic water repellency refers to the capacity of droplets to rapidly detach from solid surfaces and is usually evaluated by the contact time; it has diverse applications, such as anti-icing, water proofing, self-cleaning, etc. Although various functional surfaces with nonwettability have been designed and fabricated to provide dynamic water repellency with a certain extent of application potential, the underlying physics of bouncing dynamics of impact droplets is still needed to be studied for more rational explanation of some special phenomena, especially under low-temperature conditions. On the basis of experimental studies and theoretical calculations, we analyzed the critical condition between rebounding and splashing of impact droplets on the hierarchical-structured superhydrophobic surfaces. Subsequently, the rebounding process was considered as the research object for revealing the action mechanism of triple-phase contact line on mediating the dynamic water repellency. All these physics will help to analyze the anti-icing mechanism of anti-icing/icephobic materials with the aim to well repel the coming supercooled droplets

Bioinspired Fabrication of Hierarchical-Structured Superhydrophobic Surfaces To Understand Droplet Bouncing Dynamics for Enhancing Water Repellency

Dynamic water repellency refers to the capacity of droplets to rapidly detach from solid surfaces and is usually evaluated by the contact time; it has diverse applications, such as anti-icing, water proofing, self-cleaning, etc. Although various functional surfaces with nonwettability have been designed and fabricated to provide dynamic water repellency with a certain extent of application potential, the underlying physics of bouncing dynamics of impact droplets is still needed to be studied for more rational explanation of some special phenomena, especially under low-temperature conditions. On the basis of experimental studies and theoretical calculations, we analyzed the critical condition between rebounding and splashing of impact droplets on the hierarchical-structured superhydrophobic surfaces. Subsequently, the rebounding process was considered as the research object for revealing the action mechanism of triple-phase contact line on mediating the dynamic water repellency. All these physics will help to analyze the anti-icing mechanism of anti-icing/icephobic materials with the aim to well repel the coming supercooled droplets