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为明确烟粉虱在入侵过程中的寄主选择性与其化学感受系统对寄主植物挥发物的分子识别之间的相互作用和化学机理,通过荧光、紫外光谱和圆二色谱等技术分析了烟粉虱化学感受蛋白Bt CSP1与一种重要的植物挥发物成分—β-紫罗兰酮之间的相互作用。结果表明,β-紫罗兰酮与Bt CSP1在不同温度时的猝灭机理不同,300 K(27℃)时二者的亲和力较弱,表观结合常数KA为2.44×105L/mol,较低温290 K(17℃)和高温310 K(37℃)时的3.22×105L/mol和3.23×105L/mol均要低,表明Bt CSP1与β-紫罗兰酮在不同的温度下呈现不同的结合机理,低温时为静态猝灭,而高温时为动态猝灭。通过热力学参数和非辐射能量转移理论分析,β-紫罗兰酮与Bt CSP1蛋白结合时发生了荧光共振能量转移,结合距离为5.2 nm。圆二色谱结果显示,随着β-紫罗兰酮浓度的升高,Bt CSP1蛋白中α-螺旋比例逐渐减少,由纯蛋白时的63%下降到55.9%,二级结构发生了变化。
In order to clarify the interaction and chemical mechanism between the host selectivity of Bemisia tabaci (Gennadius) and its molecular recognition of the host plant volatiles by biosensors, the biotypes of Bemisia tabaci (Gennadius) were analyzed by fluorescence, UV and circular dichroism Interaction between chemosensory protein Bt CSP1 and β-ionone, an important plant volatile component. The results showed that the quenching mechanism of β-ionone and Bt CSP1 at different temperatures was different. At 300 K (27 ℃), the affinity between β-ionone and Bt CSP1 was weaker. The apparent binding constant KA was 2.44 × 105 L / mol and 290 K (17 ℃) and high temperature of 310 K (37 ℃), 3.22 × 105 L / mol and 3.23 × 105 L / mol, respectively, indicating that Bt CSP1 and β-ionone exhibit different binding mechanisms at different temperatures. Quenching for static, and dynamic quenching for high temperatures. Through thermodynamic parameters and non-radiative energy transfer theory, fluorescence resonance energy transfer occurs when β-ionone binds to Bt CSP1 protein with a binding distance of 5.2 nm. The results of circular dichroism showed that the α-helix proportion of Bt CSP1 protein decreased gradually with the increase of β-ionone concentration from 63% to 55.9% of pure protein, and the secondary structure changed.