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Objective To prepare PTD4-Cu,Zn-SOD fusion protein.Methods The recombinant plasmid of pET 1 6b-Cu,Zn-SOD and pET16b-PTD4-Cu,Zn-SOD was transformed into Escherichia coli BL21 (DE3).Isopropyl β-D-1-thiogalactopyranoside was then added at a final concentration of 0.84 mmol/L,and the cells were incubated for 4 h to induce the expression of Cu,Zn-SOD and PTD4-Cu,Zn-SOD fusion protein.Lysozyme and ultrasound were used to lyse the bacteria,the supernatant was collected for 15％ SDS-PAGE to analyze the expression of the target protein.Ni-NTA His bind resin was used to purify Cu,Zn-SOD protein and PTD4-Cu,Zn-SOD fusion protein under natural conditions.Western blot was used to identify the target protein.Results The results of Western blot showed that the purity of the target protein was about 90％,and the Cu,Zn-SOD protein with a molecular weight about 19 kDa and the PTD4-Cu,Zn-SOD fusion protein with a molecular weight about 20 kDa were found.Conclusion PTD4-Cu,Zn-SOD fusion protein is prepared successfully.
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γ-Secretase is aⅠtransmembrane protease associated with Alzheimer disease(AD), and including four subunits:presenilin,presenilin enhancer-2,anterior-pharynx-defective1 and nicastrin. In recent studies,the ultra-high-resolution cryo-electron microscope has been used for the first time, revealing the humanγ-secretase″horseshoe″,the three-dimensional structure and the arrangement of the subunits. This technique has shed light on the regulation of the enzyme pathway and mechanism. In addition,the γ-secretase modulators,including non-steroidal anti-inflammatory drugs,have been shown in vitro to inhibit γ-secretase activity and selectively reduce the level of Aβ42 against AD. They have provided an effective approach,with broad prospects for development. Studies in this area have become a hot topic in recent years. Here we summarized the γ-secretase subunits regulatory pathways, humanγ-secretase fine three-dimensional structure andγ-secretase modulators .
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Objective To construct the prokaryotic recombinant expression vector of PTD4-Cu,Zn-SOD.Methods By using the techniques of gene recombination,the primers of Cu,Zn-SOD and the oligonucleotide sequences of PTD4 were designed,PCR amplification was performed for Cu,Zn-SOD genes,the PCR products were identified,reclaimed and purified,and pET16b served as carrier.The prokaryotic recombinant expression vector of pET16b-Cu,Zn-SOD was constructed using double digestion with Xho Ⅰ and BamH Ⅰ,ligated reaction and plasmid transformation.Then PTD4 gene and pET16b-Cu,Zn-SOD carrier were double digested with Nde Ⅰ and Xho Ⅰ and ligated,and the plasmid was transformed,and the prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD was constructed.The reconstructed vector was analyzed by restriction mapping and was verified by gene sequencing.Results The prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD with a length of 6 207 bp was constructed successfully.The carrier fragment about 5.7 kp and PTD4-Cu,Zn-SOD gene fragment about 510 bp were obtained by double digestion with Nde Ⅰ and BamH Ⅰ,which was consistent with the expected results.The results of gene sequencing showed that the base sequences of pET16b-PTD4-Cu,Zn-SOD were correct when compared with the expected gene sequences.Conclusion The prokaryotic recombinant expression vector of pET16b-PTD4-Cu,Zn-SOD is constructed successfully.
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KM-HN-1 is a C-terminal coiled-coil domain containing protein previously referred to as image clone MGC33607. This protein has been previously identified as a cancer/testis antigen and reported as nuclear and chromatin localizing protein. We raised polyclonal antisera with the GST fusion protein and identified them as a 105 kDa protein. Motif analysis showed that this protein harbors the leucine zipper motif in internal 1/3 region and the coiled-coil domain in the C-terminal region. Using the full length and various deletion mutants, we determined the motif that governs the subcellular localization of KM-HN-1. Immunofluorescence staining of the endogenous KM-HN-1 and various kinds of GFP-tagged KM-HN-1 revealed that KM-HN-1 localizes to the centrosomes as well as nucleus. The centrosomal localization-determining region of this protein is C-terminal coiled-coil domain in which the leucine zipper motif and the nuclear export signal (NES) harbor.