重组蓝细菌藻蓝蛋白RpcA共价偶联多种藻胆色素

Covalent attachment of various phycobilins to recombinant cyanobacteria phycocyanin RpcA

利用建立的藻胆蛋白大肠杆菌异源表达系统,证明了Synechococcus sp.WH8102的藻蓝蛋白α亚基RpcA能分别结合蓝细菌中的4种藻胆素.裂合酶RpcG利用PCB或PEB做色素底物,连接它们到RpcA上,并伴随着异构作用,分别生成色素蛋白PVB-RpcA、PUB-RpcA;但裂合酶CpcE/CpcF利用PCB或PEB做色素底物,连接它们到RpcA上,则分别生成了色素蛋白PCB-RpcA、PEB-RpcA.后者荧光量子产率较高.2种裂合酶使用2种不同的色素底物,可以产生4种完全不同的、仅偶联到RpcA的色素蛋白.RpcG和CpcE/CpcF的对比研究可以探讨裂合酶异构功能的结构基础.同时这些色素蛋白有潜在的应用价值,可以作为生物学荧光探针。

Researchers have discovered the enzymes that synthesize phyeobilin chromophores as well as many of the phycobilin lyase enzymes that attach these chromophores to their apoproteins. Here by conveniently heterologous expression in Escherichia coli, all four phycobilins in cyanobacterium were respectively covalently attached to α subunit of phycocyanin from the marine cyanobacterium Synechococcus sp. WHS102. The lyaseIsomerase RpcG used PEB or PCB as substrates and attach them, with concomitant isomerization, to RpcA, respectively producing PUB-RpcA or PVB-RpcA. But the bilin lyases CpcE/CpcF took PEB or PCB as substrates and attach them, without lsomerlzatlon exhibited a hig produced four comparison be to RpcA, respectively forming PEB-RpcA or h-fluorescence quantum yield. Two lyases used distinct chromoproteins, respectively bound tween RpcG and CpcE/CpcF can investigate PCB-RpcA. The latter two bilin substrates to the same RpcA. the struc isomerization. At the same time, these biliproteins have potential fluorescent biological markers. tural basis application and A of inIsomerase RpcG used PEB or PCB as substrates and attach them, with concomitant isomerization, to RpcA, respectively producing PUB-RpcA or PVB-RpcA. But the bilin lyases CpcE/CpcF took PEB or PCB as substrates and attach them, without lsomerlzatlon exhibited a hig produced four comparison be to RpcA, respectively forming PEB-RpcA or h-fluorescence quantum yield. Two lyases used distinct chromoproteins, respectively bound tween RpcG and CpcE/CpcF can investigate PCB-RpcA. The latter two bilin substrates to the same RpcA. the struc isomerization. At the same time, these biliproteins have potential tural basis application and A of in fluorescent biological markers.