The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monit...The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.展开更多
传统抗体偶联药物(antibody drug conjugates,ADC)通过将单克隆抗体与细胞毒性药物相结合,实现对癌细胞的精准打击,但在稳定性、靶向性、疗效及安全性等方面依然存在诸多不足。新型ADC,如双特异性、位点特异性、双有效载荷和前药型ADC,...传统抗体偶联药物(antibody drug conjugates,ADC)通过将单克隆抗体与细胞毒性药物相结合,实现对癌细胞的精准打击,但在稳定性、靶向性、疗效及安全性等方面依然存在诸多不足。新型ADC,如双特异性、位点特异性、双有效载荷和前药型ADC,通过同时结合2个不同抗原或表位、选择更稳定的连接子、与抗体特定氨基酸位点偶联、携带不同药物有效载荷以及采用前药策略等优化方法,在保留传统ADC作用特点的基础上,显著提高药物的稳定性、靶向性、疗效和安全性,能更好地满足临床治疗的需求。新型ADC可能会在未来的癌症治疗中发挥重要的作用。探讨新型ADC在癌症治疗中的进展并分析其优势与挑战,可为开发抗癌策略提供理论支持,为药物研发提供方向。展开更多
PAP2(Production of anthocyanin pigment 2)编码MYB转录因子,与bHLH、WD40形成MYB-bHLH-WD40复合体来调控花青素合成。本研究从埃塞俄比亚芥和黑芥中分别克隆出2个和1个PAP2基因拷贝,分别命名为BcaB.PAP2、BcaC.PAP2、BniB.PAP2,这三...PAP2(Production of anthocyanin pigment 2)编码MYB转录因子,与bHLH、WD40形成MYB-bHLH-WD40复合体来调控花青素合成。本研究从埃塞俄比亚芥和黑芥中分别克隆出2个和1个PAP2基因拷贝,分别命名为BcaB.PAP2、BcaC.PAP2、BniB.PAP2,这三个基因均由3个外显子和2个内含子组成,均编码247个氨基酸。基于本研究克隆的PAP2基因序列和已报道的其他芸薹属PAP2基因序列,设计了3对能分别检测A、B、C基因组PAP2基因的引物,通过等位特异PCR可以区分芸薹属禹氏三角中的6个物种PAP2的基因组来源。选取芥菜型油菜B基因组的BjuB.PAP2基因构建过表达载体,转化拟南芥,其叶片变紫,表明PAP2基因正调控花青素合成。遮光处理10天后紫叶埃塞俄比亚芥的叶片紫色变淡,花青素含量下降了41.22%。荧光定量PCR和转录组研究表明,遮光处理植株叶片中BcaB.PAP2和BcaC.PAP2表达量均下降,花青素合成的结构基因查尔酮合成酶基因(CHS)、查尔酮异构酶基因(CHI)、黄烷酮3-羟化酶基因(F3H)、二氢黄酮醇还原酶基因(DFR)、花青素合成酶基因(ANS)、类黄酮3-葡糖基转移酶基因(UFGT)等基因的表达量也下降。本研究完成了对芸薹属植物中埃塞俄比亚芥和黑芥PAP2基因的克隆,并对其进行进化分析。根据本实验中克隆及其他已报道的PAP2基因序列设计等位基因特异性PCR引物,为芸薹属种间杂交后代PAP2基因的基因组传递鉴定提供了分子标记。通过BjuB.PAP2基因转拟南芥植株结果表明PAP2基因参与花青素的积累。紫叶埃塞俄比亚芥经遮光处理后,发现BcaPAP2基因及花青素合成结构基因的表达受光照的诱导。本研究在芸薹属中克隆PAP2基因,并初步验证PAP2的功能,为进一步解析芸薹属植物花青素合成的调控机制提供参考。展开更多
基金湖南省教育厅基金优秀青年项目(No.22B0482)湖南科技大学博士启动基金(No.E51992 and E51993)资助。
文摘The xylitol dehydrogenase(XDH)is a crucial enzyme involved in the xylose utilization in pentose⁃catabolizing yeasts and fungi.In addition to producing xylulose,XDH can also be employed to develop a biosensor for monitoring xylitol concentration.In this study,the gene encoding the thermophilic fungus Talaromyces emersonii XDH(TeXDH)was heterologously expressed in Escherichia coli BL21(DE3)at 16℃in the soluble form.Recombinant TeXDH with high purity was purified by using a Ni⁃NTA affinity column.Size⁃exclusion chromatography and SDS⁃PAGE analysis demonstrated that the puri⁃fied recombinant TeXDH exists as a native trimer with a molecular mass of approximately 116 kD,and is composed of three identical subunits,each with a molecular weight of around 39 kD.The TeXDH strictly preferred NAD^(+)as a coenzyme to NADP^(+).The optimal temperature and pH of the TeXDH were 40℃and 10.0,respectively.After EDTA treatment,the enzyme activity of TeXDH decreased to 43.26%of the initial enzyme activity,while the divalent metal ions Mg^(2+)or Ca^(2+)could recover the enzyme activity of TeXDH,reaching 103.32%and 110.69%of the initial enzyme activity,respectively,making them the optimal divalent metal ion cofactors for TeXDH enzyme.However,the divalent metal ions of Mn^(2+),Ni^(2+),Cu^(2+),Zn^(2+),Co^(2+),and Cd^(2+)significantly inhibited the activity of TeXDH.ICP⁃MS and molecular doc⁃king studies revealed that 1 mol/L of TeXDH bound 2 mol/L Zn^(2+)ions and 1 mol/L Mg^(2+)ion.Further⁃more,TeXDH exhibited a high specificity for xylitol,laying the foundation for the development of future xylitol biosensors.
文摘传统抗体偶联药物(antibody drug conjugates,ADC)通过将单克隆抗体与细胞毒性药物相结合,实现对癌细胞的精准打击,但在稳定性、靶向性、疗效及安全性等方面依然存在诸多不足。新型ADC,如双特异性、位点特异性、双有效载荷和前药型ADC,通过同时结合2个不同抗原或表位、选择更稳定的连接子、与抗体特定氨基酸位点偶联、携带不同药物有效载荷以及采用前药策略等优化方法,在保留传统ADC作用特点的基础上,显著提高药物的稳定性、靶向性、疗效和安全性,能更好地满足临床治疗的需求。新型ADC可能会在未来的癌症治疗中发挥重要的作用。探讨新型ADC在癌症治疗中的进展并分析其优势与挑战,可为开发抗癌策略提供理论支持,为药物研发提供方向。
文摘PAP2(Production of anthocyanin pigment 2)编码MYB转录因子,与bHLH、WD40形成MYB-bHLH-WD40复合体来调控花青素合成。本研究从埃塞俄比亚芥和黑芥中分别克隆出2个和1个PAP2基因拷贝,分别命名为BcaB.PAP2、BcaC.PAP2、BniB.PAP2,这三个基因均由3个外显子和2个内含子组成,均编码247个氨基酸。基于本研究克隆的PAP2基因序列和已报道的其他芸薹属PAP2基因序列,设计了3对能分别检测A、B、C基因组PAP2基因的引物,通过等位特异PCR可以区分芸薹属禹氏三角中的6个物种PAP2的基因组来源。选取芥菜型油菜B基因组的BjuB.PAP2基因构建过表达载体,转化拟南芥,其叶片变紫,表明PAP2基因正调控花青素合成。遮光处理10天后紫叶埃塞俄比亚芥的叶片紫色变淡,花青素含量下降了41.22%。荧光定量PCR和转录组研究表明,遮光处理植株叶片中BcaB.PAP2和BcaC.PAP2表达量均下降,花青素合成的结构基因查尔酮合成酶基因(CHS)、查尔酮异构酶基因(CHI)、黄烷酮3-羟化酶基因(F3H)、二氢黄酮醇还原酶基因(DFR)、花青素合成酶基因(ANS)、类黄酮3-葡糖基转移酶基因(UFGT)等基因的表达量也下降。本研究完成了对芸薹属植物中埃塞俄比亚芥和黑芥PAP2基因的克隆,并对其进行进化分析。根据本实验中克隆及其他已报道的PAP2基因序列设计等位基因特异性PCR引物,为芸薹属种间杂交后代PAP2基因的基因组传递鉴定提供了分子标记。通过BjuB.PAP2基因转拟南芥植株结果表明PAP2基因参与花青素的积累。紫叶埃塞俄比亚芥经遮光处理后,发现BcaPAP2基因及花青素合成结构基因的表达受光照的诱导。本研究在芸薹属中克隆PAP2基因,并初步验证PAP2的功能,为进一步解析芸薹属植物花青素合成的调控机制提供参考。
