Heterogenous expression of <Emphasis Type="Italic">Synechocystis</Emphasis> sp. PCC 6803 deg proteases and their possible roles on phycobiliprotein degradation <Emphasis Type="Italic">in vitro</Emphasis>

The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA (degP, slr1204), hhoA (degQ, sll1679) and hhoB (degS, sll1427). This work provided biochemical characterization of HhoA, HtrA and HhoB from Synechocystis sp. PCC 6803. Firstly mature HhoA, HhoB and HtrA from Synechocystis sp. PCC 6803 were cloned and expressed as soluble recombinant his-tagged fusion protein in Escherichia coli. Then the proteolytic activity of HhoA, HhoB and HtrA was tested using casein, bovine serum albumin, five recombinant chromoproteins and cyanobacterial phycocyanin as substrates in vitro. The experimental results showed that HhoA and HtrA had proteolytic activity on casein, five recombinant chromoproteins and cyanobacterial phycocyanin. No proteolytic activity of HhoB was found using all substrates in vitro, indicating functional difference among Deg proteases from Synechocystis sp. PCC 6803. Therefore, the results indicated the biochemical properties of HhoA and HtrA on hydrolysis of proteins and phycobiliproteins in vitro, which implicated that they were proteases possibly involved in phycobiliprotein degradation in vivo.     

集胞藻ApcA和CpcA的体内生物重组研究

利用聚合酶链式反应(PCR)克隆出集胞藻Synechocystis sp.PCC 6803变藻蓝蛋白和藻蓝蛋白α亚基的编码基因apcA和cpcA,将脱辅基蛋白ApcA、CpcA分别与裂合酶CpeS1或CpcE/F以及血红素氧化酶HO1、胆绿素还原酶PcyA在大肠杆菌中共同表达。研究表明:通过大肠杆菌体内重组可以获得具有光学活性的重组色素蛋白PCB-ApcA和PCB-CpcA。吸收光谱、荧光光谱以及锌电泳均表明,藻蓝胆素与脱辅基蛋白形成了正确的共价连接。由此可知,利用大肠杆菌进行集胞藻藻蓝蛋白和变藻蓝蛋白α亚基的体内生物合成是可实现的。同时还对重组色素蛋白的摩尔消光系数和荧光量子产率进行了计算。     

藻胆蛋白ApcE缺失突变体的自催化重组研究

采用聚合酶链式反应（PCR）扩增出Anabaena．sp PCC7120别藻蓝蛋白ApcE（1-240）的一系列缺失突变体基因：apcE（14—240）、apcE（25—240）、apcE（63—240）、apcE（85—240）、apcE（121—240）、apcE（133—240）、apcE（187～240），在大肠杆菌中高效表达分别获得相对应的缺失突变体蛋白。对上述脱辅基蛋白与藻蓝胆素（PCB）的体外自催化重组进行了研究。结果表明：在含有4mol／L尿素的磷酸钾缓冲体系中，ApcE（25—240）脱辅基蛋白可与藻蓝胆素体外重组实现共价连接，获得的色素蛋白质具有最大吸收峰（λmax=656rim）和荧光发射峰（λmax=670nm），其余6个缺失突变体蛋白仅能与藻蓝胆素非共价连接，不能发生自催化重组。该结果为进一步研究连接多肽ApcE的结构和功能提供了信息，具有重要意义。     

光伏产业典型污泥处置与资源化利用技术研究进展

综述了光伏产业典型污泥——氟化钙污泥的来源、危害及当前国内外处置研究现状,分析探讨了各种处置方法的可行性,指出了各项研究技术存在的优缺点,指出了在处理时可以根据实际情况进行相应处置工艺的选择。此外,对氟化钙污泥的处理和资源化利用的未来发展方向进行了评估、展望及建议。     

Heterogenous Expression of Synechocystis sp. PCC 6803 Deg Proteases and Their Possible Roles on Phycobiliprotein Degradation in vitro

The Synechocystis sp. PCC 6803 genome harbours a Deg gene family consisting of three members, htrA (degP, slr1204), hhoA (degQ, sll1679) and hhoB (degS, sll1427). This work provided biochemical characterization of HhoA, HtrA and HhoB from Synechocystis sp. PCC 6803. Firstly mature HhoA, HhoB and HtrA from Synechocystis sp. PCC 6803 were cloned and expressed as soluble recombinant his-tagged fusion protein in Escherichia coli. Then the proteolytic activity of HhoA, HhoB and HtrA was tested using casein, bovi...