| 1. | The mutations at 16 positions were found for the first time
其中16个突变位点未见过报道。 |
| 2. | The low - enzyme activity gene has 2 base changes , resulting in short amino acid sequence with native enzyme
其中低酶活基因编码区内一突变位点导致氨基酸序列的提前终止。 |
| 3. | Similarity analysis shows that some results were incongruent with the traditional taxonomy , e . g
核苷酸序列中存在25处突变位点，主要出现于fachb439和fachb440两个品系中。 |
| 4. | The other amylase activity is 40 times of native amylase . the non - amylase activity gene has 9 base changes , resulting in 5 amino acid changes from the native enzyme
其中，无酶功能基因突变位点最多，导致全长编码区内5个氨基酸突变，低酶活和高酶活基因各两个突变位点。 |
| 5. | Thirdly , the expected mutants were introduced into the sed dna by megaprimer pcr . then the expressed mutants were purified and analyzed with immunoblot . the results showed that these sed mutants could be used in the subsequent functional study
3 ，以丙氨酸扫描突变方案，采用大引物pcr技术，在选定的突变位点处成功引入预期突变，构建了sedn23a 、 sedf45a 、 sedl59a 、 sen6la 、 sedi92a和sedfz 。 |
| 6. | The deduced amino acid sequence of the epsp synthase from psedomonas fluorescens g2 was compared to epsp synthase from various species . it shares 30 % homology with the epsp synthases from e . coli and salmonella typhimurium in class i and is different from patent - protected mutational sites
将本实验获得的荧光假单胞菌g2epsp合成酶推导的氨基酸序列与class中大肠杆菌和鼠伤寒沙门氏菌来源的epsp合成酶同源性约为30 ，且不含有专利保护的突变位点。 |
| 7. | After absorption , the all - frans - retinal isomerizes to a 13 - c / s configuration and br undergoes a photocycle : br570 k590 l550 m410 n520 o640 br570 bacteriohodopsin is a promising biological photoelectric material . we intent to conduct a more thermostable br by site - directed mutagensis . a point ( no . 274 t , no . 274 a turn to c g ) mutation was introduced to br gene by successive pcr technique , and cloned into puc - 19 vector
本论文利用连续pcr的方法定点突变了br基因的一个氨基酸，突变位点选择了br基因第273的t和274位的a ，把它们变为cg ( tyr替换为arg ) ，然后把突变的br基因克隆入嗜盐菌表达载体pnov - r ，经测序鉴定的表达载体转化br缺陷的嗜盐菌，构建了tyr79 argbr突变体。 |
| 8. | It shares less than 25 % homology with the epsp synthases in class ii . it also shares 24 . 5 % homology with the epsp synthase isolated by monsanto company and does not contain any conservative sequences and mutational sites protected by patents . all of the above shows great potential for future development
与class的epsp合成酶同源性低于25 ，其中与monsanto公司分离的根癌农杆菌( agrobacteriumtumefaciens ) cp4来源的epsp合成酶同源性仅为24 . 5 ，且不含有专利保护的保守序列和突变位点，显示了良好的开发应用潜力。 |
| 9. | Secondly , we compared the amino acid sequences of ses and constructed the three - dimension structure of sed by homology modeling method . on the basis of results of comparing the amino acid sequences and structure of sed iv with other ses , we chosen the n23 , f45 , l59 , n61 , 192 and f203 in sed as mutant residues
对金葡菌超抗原家族的氨基酸序列进行对比分析，首次运用同源建模的方法构建了sed的三维空间结构模型，比较sed与其它肠毒素超抗原结构的差异，对可能的活性位点进行预测，最终确定sed的n23 、 f45 、 l59 、 n6 、 192和f203位氨基酸为突变位点。 |
| 10. | Of seven sweet - taste proteins , brazzein has smallest molecular mass , simply molecular structure and is most heat - stable . in order to make use of brazzein , we have studying on the expression of brazzein gene in e . coli and plants : lettuce and tobacco . the results obtained are summarized below
为了更好的利用甜蛋白，探讨brazzein基因在原核生物和植物中的表达，本论文进行了一些研究，结果如下： 1以合成的brazzein基因为模板，通过引物设计引入突变位点，在基因5 ’末端引入ala的密码子替代原有序列中编码pglu的密码子。 |
