Retraction Note: Gold Nanoparticles‑enabled Efficient Dual Delivery of Anticancer Therapeutics to HeLa cells

The editors have retracted their article Gold Nanoparticles-enabled Efficient Dual Delivery of Anticancer Therapeutics to HeLa cells. Concerns were brought to the attention of the Editors with respect to apparent inappropriate manipulation of the data in seven of the nine panels shown in Figure 7. The Editors no longer have confidence in the data reported in this Article

Profiling Mechanisms of Alkane Hydroxylase Activity In Vivo Using the Diagnostic Substrate Norcarane

SummaryMechanistically informative chemical probes are used to characterize the activity of functional alkane hydroxylases in whole cells. Norcarane is a substrate used to reveal the lifetime of radical intermediates formed during alkane oxidation. Results from oxidations of this probe with organisms that contain the two most prevalent medium-chain-length alkane-oxidizing metalloenzymes, alkane ω-monooxygenase (AlkB) and cytochrome P450 (CYP), are reported. The results—radical lifetimes of 1–7 ns for AlkB and less than 100 ps for CYP—indicate that these two classes of enzymes are mechanistically distinguishable and that whole-cell mechanistic assays can identify the active hydroxylase. The oxidation of norcarane by several recently isolated strains (Hydrocarboniphaga effusa AP103, rJ4, and rJ5, whose alkane-oxidizing enzymes have not yet been identified) is also reported. Radical lifetimes of 1–3 ns are observed, consistent with these organisms containing an AlkB-like enzyme and inconsistent with their employing a CYP-like enzyme for growth on hydrocarbons

Cell-Free Synthetic Biology Chassis for Nanocatalytic Photon-to-Hydrogen Conversion

We report on an entirely man-made nano-bio architecture fabricated through noncovalent assembly of a cell-free expressed transmembrane proton pump and TiO₂ semiconductor nanoparticles as an efficient nanophotocatalyst for H₂ evolution. The system produces hydrogen at a turnover of about 240 μmol of H₂ (μmol protein)⁻¹ h^–1 and 17.74 mmol of H₂ (μmol protein)⁻¹ h^–1 under monochromatic green and white light, respectively, at ambient conditions, in water at neutral pH and room temperature, with methanol as a sacrificial electron donor. Robustness and flexibility of this approach allow for systemic manipulation at the nanoparticle–bio interface toward directed evolution of energy transformation materials and artificial systems