Probing the remarkable thermal kinetics of visual rhodopsin with E181Q and S186A mutants.

We recently reported a very unusual temperature dependence of the rate of thermal reaction of wild type bovine rhodopsin: the Arrhenius plot exhibits a sharp "elbow" at 47 °C and, in the upper temperature range, an unexpectedly large activation energy (114 ± 8 kcal/mol) and an enormous prefactor (10 s). In this report, we present new measurements and a theoretical model that establish convincingly that this behavior results from a collective, entropy-driven breakup of the rigid hydrogen bonding networks (HBNs) that hinder the reaction at lower temperatures. For E181Q and S186A, two rhodopsin mutants that disrupt the HBNs near the binding pocket of the 11-cis retinyl chromophore, we observe significant decreases in the activation energy (∼90 kcal/mol) and prefactor (∼10 s), consistent with the conclusion that the reaction rate is enhanced by breakup of the HBN.

Correction: A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface.

Correction for 'A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface' by Zhuguang Wang et al., Chem. Commun.

Computer-aided design, structural dynamics analysis, and in vitro susceptibility test of antibacterial peptides incorporating unnatural amino acids against microbial infections.

Background And Objective: Antibacterial peptides (ABPs) are essential components of host defense against microbial infections present in all domains of life. The AMPs incorporating unnatural amino acids (uABPs) exhibit several advantages over naturally occurring AMPs based on factors such as bioavailability, metabolic stability and overall toxicity.

Methods: Computer-aided modeling and in vitro susceptibility test were combined to rationally design short uABPs with potent antimicrobial activity.

A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface.

We characterized BslA, a bacterial biofilm protein, at the air/water interface using vibrational sum frequency generation spectroscopy and observed one of the sharpest amide I bands ever reported. Combining methods of surface pressure measurements, thin film X-ray reflectivity, and atomic force microscopy, we showed extremely ordered BslA at the interface.

Sensitive detection of cyanide using bovine serum albumin-stabilized cerium/gold nanoclusters.

A simple, sensitive, and selective fluorescence assay for the detection of CN(-) has been demonstrated using bovine serum albumin-stabilized cerium/gold nanoclusters (BSA-Ce/Au NCs). When excited at 325 nm, BSA-Ce/Au NCs have two fluorescence bands centered at 410 and 658 nm, which are assigned to BSA-Ce/Au complexes and Au NCs, respectively. Each BSA-Ce/Au NC contains 22 Au atoms and 8 Ce ions.

Knockdown of ATPsyn-b caused larval growth defect and male infertility in Drosophila.

The ATPsyn-b encoding for subunit b of ATP synthase in Drosophila melanogaster is proposed to act in ATP synthesis and phagocytosis, and has been identified as one of the sperm proteins in both Drosophila and mammals. At present, its details of functions in animal growth and spermatogenesis have not been reported. In this study, we knocked down ATPsyn-b using Drosophila lines expressing inducible hairpin RNAi constructs and Gal4 drivers.

One-pot synthesis of fluorescent BSA-Ce/Au nanoclusters as ratiometric pH probes.

A facile, one-pot synthetic approach has been developed for the preparation of BSA-Ce/Au NCs. The fluorescence intensities of BSA-Ce/Au NCs at 410 and 650 nm are pH dependent and independent, respectively. The fluorescence intensity ratio (I410/I650) is linear against pH values from 6.

Photoluminescent organosilane-functionalized carbon dots as temperature probes.

Organosilane-functionalized carbon dots (SiC-dots) were prepared by a simple one-pot hydrothermal approach. The photoluminescence (PL) properties of the SiC-dots revealed a reversible response toward the temperature (293-343 K). Through Si-O-Si bonding, temperature-sensitive PL SiC-dot films could be easily fabricated on glass substrates.