用不同蛋白质分析方法鉴定玉米分泌蛋白组的比较研究

玉米根系在生长过程中向根际分泌蛋白质类大分子物质。采用双向聚丙烯酰胺凝胶电泳-质谱技术,一维液相色谱-质谱联用(LC/MS)和Shotgun三种不同鉴定方法对无菌条件收集的玉米根系分泌蛋白进行了分离、分析与鉴定,对3种鉴定方法在分泌蛋白分析中的应用做了详细阐述和比较。结果表明,双向电泳通过银染可以看到200个蛋白质点,但由于蛋白量少,通过质谱无法对玉米根系分泌蛋白进行鉴定;用LC/MS鉴定得到了152个蛋白;用Shotgun技术鉴定得到了2 848个蛋白。LC/MS鉴定得到的蛋白全部出现在用Shotgun技术鉴定得到的2 848个蛋白中,后2种方法的结果可以互相验证。Shotgun技术具有更高的灵敏性,更适合对蛋白质浓度低、干扰物多的植物根分泌蛋白组进行鉴定,能够获得完整可靠的信息。

Comparative studies on identification of maize secreted proteome by different analyzing techniques

Maize roots release a battery of proteins into the rhizosphere during growth and development. In the present study, mucilage secreted by primary roots of 3-4 d old maize seedlings was collected under axenic conditions, and the constitutively secreted proteins were analyzed by different methods, including two-dimensional electrophoresis--MADLI-TOF, LC-MS, and Shotgun techniques. The results showed that 200 protein spots could be observed on two-dimensional electrophoresis gel stained by silver nitrate. However, due to the low protein content for each protein spot, there was not reliable result after identification by MADLI-TOF. On the other hand, 152 and 2848 proteins were identified by LC/MS and Shotgun technique, respectively. All 152 proteins identified by LC/MS method could be found in the proteins identified by Shotgun method, and thus the results obtained by LC/MS and Shotgun method could be authenticated mutually. The results demonstrated that the Shotgun method is more sensitive than the other methods for protein identification, especially for the proteins with lower contents and complex interfering substances, such as the plant root released proteins.