【摘 要】
：
1,3-propanediol (1,3-PD) is an important material for chemical industry, and there has been always much interest in the production of 1,3-PD using all possible
【机 构】
：
Guangxi Key Laboratory of Subtropical Bioresource Conservation and Utilization,Guangxi Academy of Sc
论文部分内容阅读
1,3-propanediol (1,3-PD) is an important material for chemical industry, and there has been always much interest in the production of 1,3-PD using all possible routes. The genes encoding glycerol dehydratase (GDHt) from Citrobacter freundii,Klebsiella pneumoniae and metagenome were cloned and expressed in E. coli. All glycerol dehydratases but the one from metagenome could be detected to show enzyme activities. In order to improve the enzymatic properties of GDHts, the genes encoding α and β-γ subunits were cloned, and the enzyme characteristics were evolved by rational design based on their 3D structures which were constructed by homology modeling. Six heteroenzymes were obtained by swapping the α subunit genes of these three different-source-derived GDHts. The pH,thermal stability and Vmax of some heteroenzymes were dramatically improved by 2-5 times compared with the wild one (GDHtKP). The GDHt cloned from metagenome, originally proved to be with no enzyme activity, was converted into active enzyme by swapping its subunits with other different GDHts. In addition, the effect of subtle 3D structural changes on the properties of the enzyme was also observed.
其他文献
我部训练基地远离市区,工厂、生活的“硬件”设施落后,加上主观方面的原因,致使我们的队伍在思想政治工作方面存在种种问题。对这些问题的解决,要以理想信念教育为核心,以思
Based on the model structure of the influence coefficient method analyzed in depth by matrix theory,it is explained the reason why the unreasonable and instable
By using the output inductors and body capacitances without adding any component compared with hard switching synchronous rectifier,the topology of a soft switc
李某,男,16岁,学生.2002年5月9日初诊.主诉:头昏、不能行走2月余,阵发性抽搐、角弓反张1月余.
The precise detection of flaw echoes buried in backscattering noise caused by material microstructure is a problem of great importance in ultrasonic non-destruc
In e-commerce the multidimensional data analysis for OLAP (on-line analytical processing) based on the web data needs integrating various data sources such as X
近些年,一些职高学校的语文教师反映在职高学校中开展语文课程难度较以往有所增加。这种现象主要是由几方面原因造成的,其中,由于社会变更速度加快,人们的心理随之不断变化,
在推进素质教育，推进自主学习的宏观进程中，围绕如何选择有效的教学途径，提高学生学习效率的问题，可谓仁者见仁，智者见智，争议颇多。做为一个中学教师，近年来，我在认真学习教育理论的
Treated FeS2 samples were prepared by natural FeS2 samples which were ground first,heated in nitrogen and then washed in acid. The levels of impurity elements,
This paper reviews the investigation status of the techniques for preparation of metal matrix composites and the research outcomes achieved recently. The mechan