Effect of real-world sounds on protein crystallization.

Protein crystallization is sensitive to the environment, while audible sound, as a physical and environmental factor during the entire process, is always ignored. We have previously reported that protein crystallization can be affected by a computer-generated monotonous sound with fixed frequency and amplitude. However, real-world sounds are not so simple but are complicated by parameters (frequency, amplitude, timbre, etc.) that vary over time. In this work, from three sound categories (music, speech, and environmental sound), we selected 26 different sounds and evaluated their effects on protein crystallization. The correlation between the sound parameters and the crystallization success rate was studied mathematically. The results showed that the real-world sounds, similar to the artificial monotonous sounds, could not only affect protein crystallization, but also improve crystal quality. Crystallization was dependent not only on the frequency, amplitude, volume, irradiation time, and overall energy of the sounds but also on their spectral characteristics. Based on these results, we suggest that intentionally applying environmental sound may be a simple and useful tool to promote protein crystallization.

A chiral BINOL-based Gemini amphiphilic gelator and its specific discrimination of native arginine by gelation in water.

A novel axially chiral cationic Gemini amphiphile gelator (S1) derived from (S)-BINOL has been synthesized and characterized by 1H NMR, 13C NMR, ESI-MS and FT-IR analyses. The critical micelle concentration (CMC) of S1 was determined to be 0.21 mM in water at room temperature. A transparent hydrogel with S1 at 43 mM was obtained at room temperature and characterized using various methods including SEM, CD, fluorescence, 1H NMR, FT-IR, and XRD. The results indicate that the hydrophobic effect of long alkyl chains, π-π stacking of naphthalene rings, and intermolecular hydrogen-bonding of the amide groups of S1 should be responsible for the hydrogel formation. Moreover, an 8.5 mM aqueous solution of S1 could gel by the addition of l-arginine, whereas it failed to gel in the presence of other 15 amino acids, respectively. It is suggested that S1 could discriminate native arginine by hydrogel formation, mainly due to the electrostatic interaction and hydrogen bonding effects between S1 and l-arginine molecules.

Bi-8-carboxamidoquinoline derivatives for the fluorescent recognition of Zn2+.

Three fluorescent sensors which were composed of a phendiol (o-, m-, p-isomers) and two carboxamidoquinolines have been synthesized and characterized. Research on the Zn(2+)-sensing properties of the three sensors was carried out, and the results showed a significant difference in the recognition performance for Zn(2+). The fluorescence intensity (I(510 nm)) of ortho isomeric sensor binding to Zn(2+) was enhanced 23-fold, the meta 15-fold, the para 8-fold. As the distance between two carboxamidoquinolines became longer, the fluorescence enhancement decreased. In addition, the selectivity of sensors got poor and the detection limit became higher with rising the distance between two receptors.