长双歧杆菌NCC2705葡萄糖与果糖代谢的比较蛋白质组学

Comparative Proteome Analysis of Bifidobacterium longum NCC2705 Grown on Fructose and Glucose

为揭示长双歧杆菌NCC2705(Bifidobacterium longum NCC2705)果糖代谢途径,建立其果糖发酵模型。以本实验室前期构建的长双歧杆菌NCC2705菌株蛋白质参考图谱为基础,进行了果糖和葡萄糖生长的菌体比较蛋白质组学研究,利用MALDI-TOF和ESI-MS/MS鉴定差异蛋白,进一步通过半定量RT-PCR验证二者显著差异表达蛋白。果糖生长的菌体蛋白中鉴定到了所有葡萄糖降解途径中的酶和蛋白质,另外鉴定到3倍以上差异蛋白点9个,其对应的5个蛋白在果糖发酵中上调。半定量RT-PCR验证显著差异蛋白,显示在果糖发酵中具有高水平表达是ABC转运系统的果糖特异性-结合蛋白BL0033和ATP结合蛋白BL0034。果糖的发酵时间和浓度梯度试验显示诱导时间越长、浓度越高,BL0033的表达量越高。第一,比较蛋白谱证明果糖和葡萄糖以相同途径降解。第二,BL0033的表达是受果糖诱导的,果糖的吸收可能是通过一个特殊的转运系统,即ABC转运系统将果糖从胞外转运到胞内,其中BL0033和BL0034共同作为系统元件扮演了重要角色。

To demonstrate the fructose metabolism pathway in Bifidobacterium Longum NCC2705 and to construct its fermentation model, we explored the comparative proteome cultivating the strain on glucose or fructose, based on a proteomic reference map of B. longum NCC2705 constructed earlier. Then, we used matrix-assisted laser desorption/ionization time of flight （MALDI-TOF） mass spectrometry and electro-spray ionization tandem mass spectrometry （ESI-MS/MS） for differently expressed proteins identification. Furthermore, with semi-quantitative RToPCR we determined the distinctively expressed proteins at the level of transcription. Proteomic comparison of glucose- and fructose-grown cells demonstrated much similarity. On the page of fructose there were all the enzymes and proteins that exist during the process of glucose degradation. We observed a greater variation of more than three-fold for the identified 9 spots representing 5 protein entries by MALDI-TOF MS. The sugar-binding protein specific to fructose （BL0033） and an ABC transporter ATP binding protein （BL0034） showed higher expression level from cells grown on fructose. It was also determined by semi-quantitative RT-PCR subsequently. BL0033 time course and concentration experiments showed that the induction time correlated to higher fructose concentration, and increased expression of BL0033. Fructose was catabolized via the same degradation pathway as glucose at the level of proteomics. BL0033 was induced by fructose. All results suggest that the uptake of fructose into the cell may be conducted by a specific ABC transport system, in which BL0033 and BL0034 as components might have played an important role.