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1. 发明申请

WO1998004713A1 METHOD FOR CONTROLLING MOLECULAR WEIGHT OF POLYHYDROXYALKANOATES 审中-公开
标题翻译：控制聚羟基烷基酯分子量的方法
公开(公告)号：WO1998004713A1
公开(公告)日：1998-02-05
申请号：PCT/US1997013301
申请日：1997-07-25
申请人： MASSACHUSETTS INSTITUTE OF TECHNOLOGY
发明人： MASSACHUSETTS INSTITUTE OF TECHNOLOGY , SNELL, Kristi, D. , HOGAN, Scott, A. , SIM, Sang, Jun , SINSKEY, Anthony, J. , RHA, Chokyun
IPC分类号： C12N15/52
CPC分类号： C12N9/93 , C12P7/625
摘要： A method has been developed for control of molecular weight and molecular weight dispersity during production of polyhydroxyalkanoates in genetically engineered organism by control of the level and time of expression of one or more PHA synthases in the organisms. The method was demonstrated by constructing a synthetic operon for PHA production in E. coli in which the level of PHA synthase activity could be tightly controlled by placement of the synthase behind an inducible promoter. Modulation of the total level of PHA synthase activity in the host cell by varying the concentration of the inducer, isopropyl beta -D-thiogalactoside (IPTG), was found to effect the molecular weight of the polymer produced in the cell. Specifically, high concentrations of synthase activity were found to yield polymers of low molecular weight while low concentrations of synthase activity yielded polymers of higher molecular weight. Polymer molecular weight dispersity is also proportional to the amount of synthase activity, with less dispersity in polyhydroxyalkanoate compositions produced in expression systems with an initial burst of synthase activity, and higher levels of molecular weight dispersity in polyhydroxyalkanoate compositions produced in expression systems with the levels of synthase activity varied during synthesis of the polyhydroxyalkanoate.
摘要翻译：已经开发了一种通过控制生物体内一种或多种PHA合成酶的表达水平和时间来控制在遗传工程生物体内聚羟基链烷酸酯生产过程中的分子量和分子量分散性的方法。该方法通过在大肠杆菌中构建用于PHA生产的合成操纵子来证明，其中通过将合酶置于诱导型启动子后面可以严格控制PHA合酶活性的水平。发现通过改变诱导剂异丙基β-D-硫代半乳糖苷（IPTG）的浓度来调节宿主细胞中PHA合成酶活性的总水平，从而影响细胞中产生的聚合物的分子量。具体地说，发现高浓度的合成酶活性产生低分子量的聚合物，而低浓度的合成酶活性则产生较高分子量的聚合物。聚合物分子量分散度也与合成酶活性的量成比例，在具有合成酶活性的初始爆发的表达系统中产生的聚羟基链烷酸酯组合物的分散性较低，并且在表达系统中产生的聚羟基链烷酸酯组合物中较高水平的分子量分散性具有合成酶活性在聚羟基链烷酸酯的合成过程中变化。

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