Theoretical studies on electronic properties and nonlinear optical properties of dimeric phenylenvinylene 取代苯二胺类双希夫碱的二阶非线性光学性质的理论研究
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Comparing with using mulv reverse transcriptase or amv reverse transcriptase to do reverse transcription at 3 7 - 42 " c , more accurate and complete dna could be gotten by using tag dna polymerase at 72 c since dimeric structure of mrna was opened fully at high temperature 与在37 - 42用mulv或amv进行反转录相比，在较高温度下( 72 )用taqdna聚合酶进行反转录有利于正确、完整的cdna ，因为在高温下mrna的二级结构被充分打开。
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Gfral is an extracellular protein that is attached to the outer cell membrane by gpi - anchor and could not transducted signalling directly . according to the original model , a gdnf dimer first binds to either monomeric or dimeric gfral , and the gdnf - gfral complex then interacts with two ret molecules , thereby inducing their homodimerization and tyrosine autophosphorylation 传统观点认为： gdnf首先与gfr 1结合形成gdnf - gfr 1复合物，此复合物再与ret结合形成三聚体复合物，引起ret的二聚化，并引起酪氨酸残基自磷酸化，从而引起下游的信号转导。
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The n - terminus truncated mutant can not form tight dimeric and tetrameric structure , and leads to the destruction of the quaternary structure , which is quite the contrary to wild type arog . these data indicate that n - terminus of arog is not only involved in the feedback inhibition , but also plays a role in the formation of stable dimer which is an essential structure for its enzymatic activity . according to the 3d structure , " d2 " symmetry of arog , to which contributed by leu 16 , trp215 and his217 , is essential for the feedback inhibition 对“ dz ”对称性相关的氨基酸leul6 、 trpz15和hisz17进行点突变和双突变研究结果表明: l )在1mm苯丙氨酸的存在下， leul6ala 、 trpz15ala和hisz17ala能解除35一70 %的反馈抑制， t印2巧ala的比活降低65 %以上，其余两者的比活与野生型相近; 2 )在lmm苯丙氨酸的存在下，导入双点突变trpz1sai洲isz17ala和leul6hi撇isz17leu后能够完全解除arog的反馈抑制，同时保持与野生型相当的比活。
