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Molecular dynamic simulation on the conformation of mouse muscle type nAChR

Shengai SUN, Rilei YU, Yanhui ZHANG, Yanni LI,

《化学科学与工程前沿（英文）》 2010年第4卷第3期页码 348-352 doi: 10.1007/s11705-009-0284-4

摘要： A mouse muscle type nAChR model ((α1)βδγ) was built based on the cryoelectron microscopic structure of intact nAChR and the high resolution crystal structure of nAChR-α1 subunit. The conformation of the pentameric nAChR model was investigated by molecular dynamic simulation. The function of water molecule in the hydrophilic interior was clarified. The reason for Tyr127 showing two alternative conformations was discussed in detail.

关键词： pentameric hydrophilic Tyr127 cryoelectron microscopic conformation

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Turnover mechanisms of organic conformation on turbidity in drinking water

ZHONG Runsheng, ZHU Chunwei, ZHANG Xihui, GUAN Yuntao

《环境科学与工程前沿（英文）》 2007年第1卷第3期页码 276-279 doi: 10.1007/s11783-007-0046-9

摘要： The turbidity variation in artificial water and samples from a water plant was investigated in the presence of organics with different relative molecular mass. The results show that recessive turbidity existed when water chemical conditions were changing. The formation of turbidity depended on organic relative molecular mass and their conformations on particles. At higher pH and lower ionic strength, the organic chains with a more extended conformation resulted in rising turbidity of the suspension. At lower pH, the reconformation of organics took place due to charge neutralization by the proton, resulting in a decline in turbidity. The addition of NaCl and MgCl at pH 7.00 also resulted in a decrease of turbidity in the suspension. It is believed that the occurrence of recessive turbidity has a significant influence on the stability of water supply quality.

关键词： stability different turbidity occurrence supply

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Microbial community structure in different wastewater treatment processes characterized by single-strand conformation

ZHAO Yangguo, WANG Aijie, REN Nanqi, ZHAO Yan

《环境科学与工程前沿（英文）》 2008年第2卷第1期页码 116-121 doi: 10.1007/s11783-008-0018-8

摘要： In order to investigate microbial community structures in different wastewater treatment processes and understand the relationship between the structures and the status of processes, the microbial community diversity, variety and distribution in five wastewater treatment pro cesses were studied by a culture-independent genetic fingerprinting technique single-strand conformation polymorphism (SSCP). The five processes included denitrifying and phosphate-removal system (diminished N), Chinese traditional medicine wastewater treatment system (P), beer wastewater treatment system (W), fermentative biohydrogen-producing system (H), and sulfate-reduction system (S). The results indicated that the microbial community profiles in the wastewater bioreactors with the uniform status were very similar. The diversity of microbial populations was correlated with the complexity of organic contaminants in wastewater. Chinese traditional medicine wastewater contained more complex organic components; hence, the population diversity was higher than that of simple nutrient bioreactors fed with molasses wastewater. Compared with the strain bands in a simulated community, the relative proportion of some functional microbial populations in bioreactors was not dominant. Fermentative biohydrogen producer in the better condition bioreactor had only a 5% band density, and the sp. in the sulfate-reducing bioreactor had less than 1.5% band density. The SSCP profiles could identify the difference in microbial community structures in wastewater treatment processes, monitor some of the functional microbes in these processes, and consequently provide useful guidance for improving their efficiency.

关键词： technique single-strand proportion bioreactor community diversity fingerprinting technique

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Effect of succinic acid deamidation-induced modification on wheat gluten

Lan LIAO, Mouming ZHAO, Haifeng ZHAO, Jiaoyan REN, Chun CUI, Xiao HU,

《化学科学与工程前沿（英文）》 2009年第3卷第4期页码 386-392 doi: 10.1007/s11705-009-0250-1

摘要： The effect of succinic acid deamidation-induced modification on wheat gluten was investigated in the present study. The changes of surface hydrophobicity, functional properties, secondary structure, and sensibility of proteolysis of modified samples were determined. The solubility of deamidated proteins increased in the isoelectric region of untreated wheat gluten. The isoelectric point of succinic acid deamidated wheat gluten was shifted to a basic pH and existed in the broad pH regions. Foaming property and molecular flexibility of wheat gluten were improved after the modification. The hydrolysis degree of the hydrolysates in proteolysis with flavorzyme and pancreatin increased after succinic acid deamidation. Moreover, succinic acid deamidation-induced modification resulted in little change in molecular weight and secondary structure of the protein. Thus, succinic acid could facilitate unfolding protein conformation. In addition, it could improve protein-water interactions, surface properties, and sensibility of the proteolysis of the deamidated wheat gluten.

关键词： pH isoelectric conformation deamidation-induced modification molecular flexibility