第七届全国生物无机化学学术讨论会会议纪要

在国家自然科学基金委员会的支持下 ,第七届全国生物无机化学学术讨论会于 2 0 0 0年 1 1月 1—3日在华中科技大学成功召开。本次会议共收录论文 80多篇 ,近 70位代表参加了会议 ,他们分别来自全国 40所大学及中国科学院研究所。中国科学院院士王夔、倪嘉缵 ,华中科技大学校领导代表范华汉教授 ,以及国家自然科学基金委员会化学科学部无机化学科的陈荣及韩万书两位主任出席了本次会议。参加本次会议更多的是一些年轻学者 ,他们在各自的研究领域已经取得或正在取得具有一定理论意义或实用价值的科研成果 ,对今后壮大生物无机化学的研究队伍将…     

Conformational change of E. coli sulfurtransferase YgaP upon SCN− in intact native membrane revealed by fluorescence lifetime and anisotropy

The fluorescence lifetime and anisotropy analysis reveals different conformational changes of YgaP in DPC and SMA with fluorescent unnatural amino acid 7-HC incorporating in specific sites. And SMA is a good material to reflect the in situ conformation changes of protein than micelles. requirements of AST analogs.     

A novel potential-triggered SBA-15/PANI/PSS composite film for selective removal of lead ions from wastewater

In this study, a novel potential-triggered electroactive composite film consisting of mesoporous silica SBA-15, polyaniline (PANI), and polystyrenesulfonate (PSS) was fabricated in an aqueous electrolyte solution via a facile pulse potentiostatic method. The obtained composite film was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetric (TG) analysis, and scanning electron microscopy (SEM). The ion exchange properties were evaluated in a solution containing 0.1 M Pb(NO₃)₂ by using an electrochemical quartz crystal microbalance (EQCM) as well as cyclic voltammetry (CV) method. It was found that the uptake/release of Pb²⁺ ions in/from SBA-15/PANI/PSS composite film was successfully achieved by modulating the redox states of the electroactive composite film, and the composite film exhibited different ion exchange behaviors at different scan rates. Based on these results, the ion exchange mechanism was proposed. Compared with the PANI/PSS composite film, the SBA-15/PANI/PSS composite film had higher adsorption capacity as well as higher selectivity toward Pb²⁺ ions, which should be attributed to the 3D porous morphology of the composite film with more active sites in the mesoporous SBA-15. Remarkably, the film maintained a high stability over 97% even after 500 successive cycles. It is expected that this SBA-15/PANI/PSS composite film can serve as a promising electroactive material for the effective separation of Pb²⁺ ions from wastewater.

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A simple method to synthesize NiO fibers

Nickel oxide fibers with diameters 1-2 μm and lengths up to 100 μm were synthesized by a simple pyrolytic decomposition method in NaCl flux with NiSO₄ as precursor. X-Ray diffraction, X-ray photoelectron spectrum (XPS) and scanning electron microscopy (SEM) techniques were used to characterize these fibers. They have single-crystal structure, large aspect ratios and macroscopic quantity. Suitable precursor and molten NaCl environment are conjectured to be key factors in this method.     

Controlling the thermally activated delayed fluorescence of axially chiral organic emitters and their racemate for information encryption

A pair of axially chiral organic enantiomers were facilely prepared through a one-pot sequential synthesis. They exhibit circularly polarized luminescence activities and have thermally activated delayed fluorescence (TADF) and aggregation-induced emission enhancement properties. Meanwhile, these two enantiomers present remarkable and reversible thermochromism in the crystalline state, enabling dual-colour TADF switching between orange and red. However, when they form cocrystals, the resulting racemate shows opposite thermochromic behaviors. These intriguing results probably emanate from their different optical activities, leading to distinct molecular packing modes and molecular conformation variations. Moreover, information encryption based on thermochromism of organic enantiomers and their racemate has been presented for the first time. This work may expand the application scope of chiral organic luminogens and pave a new way to construct intelligent luminescent systems.

A pair of axially chiral organic enantiomers with circularly polarized thermally activated delayed fluorescence and aggregation-induced emission enhancement properties show opposite thermochromic behaviors to their racemate.     

Total synthesis of snake toxin α-bungarotoxin and its analogues by hydrazide-based native chemical ligation

A new method for α-bungarotoxin was reported by combining Fmoc-SPPS and peptide hydrazide based ligat ion strategy.     

Solution NMR spectroscopy of the human vasopressin V2 receptor, a G protein-coupled receptor

The seven-transmembrane-spanning G protein-coupled receptor (GPCR) superfamily plays many important roles in basic biology, human health, and human disease. Here, well-resolved solution NMR spectra are presented for a human GPCR, the vasopressin V2 receptor in detergent micelles. The quality of the NMR spectra indicates that backbone resonance assignments for a majority of resonances are feasible. The key to obtaining high quality spectra appears to be the coupling of methods for expressing the receptor into membranes rather than into inclusion bodies, with use of a biochemically mild lysolipid detergent for membrane extraction, protein purification, and NMR sample preparation.     

Movable partition designed for the seed‐assisted silicon ingot casting in directional solidification process

For the seed‐assisted casting process for silicon ingots, different partition blocks were designed in the directional solidification (DS) furnaces to preserve the seed crystals and optimize the thermal field in the hot‐zone. A transient global model was established to investigate the effects of different partition blocks during the solidification process. The simulation results showed that the partition blocks can significantly influence the temperature distributions and the melt flow fields. From the designed partition blocks, the movable partition block was more favorable for the seed‐assisted DS process. A suitable temperature gradient and a flat seed‐melt (s‐m) interface were obtained, which facilitated the preservation of seed crystals effectively, and an optimized crystal‐melt (c‐m) interface was achieved as well. One of the designs of the movable partition blocks was implemented in quasi‐mono crystalline silicon casting experiments and it has been confirmed that the designed movable partition block was helpful for the improvement of the single crystal area.     

影响内燃机活塞环—缸套擦伤的因素及防擦伤的摩擦学设计

阐述了内燃机活塞环－缸套擦伤的机理。分析了磨合，缸套表面形貌，活塞环外形，活塞组件的热变形与机械变形，润滑油，材料和表面覆层等因素对活塞环擦伤的影响。指出可以采用内燃机强化系数ｐｅｖｍ作为活塞环防擦伤摩擦学设计的判别特征值，从而为从设计上防止活塞环擦伤提供了思路。     

铜锌超氧化物歧化酶的突变与神经退行性紊乱的生物无机化学

本文简单介绍了铜锌超氧化物歧化酶的结构、功能及其相互关系,较为详细地讨论了与神经退行性紊乱,尤其是与肌萎性脊髓侧索硬化症有关的铜锌超氧化物歧化酶突变体的生物无机化学的研究进展,提出由该酶突变而引起的蛋白质局部结构变化和金属离子缺失,以及由此导致的氧化损伤和聚集作用可能是导致神经退行性紊乱的主要原因之一.