尽可能完全、准确地归属蛋白质分子的核磁共振(Nuclear Magnetic Resonance,NMR)谱峰,是解析可信赖、高质量的蛋白质三维空间溶液结构的首要条件.自动归属软件的开发和应用,已经方便并加快了蛋白质分子核磁共振谱峰的归属进程.然而,对...尽可能完全、准确地归属蛋白质分子的核磁共振(Nuclear Magnetic Resonance,NMR)谱峰,是解析可信赖、高质量的蛋白质三维空间溶液结构的首要条件.自动归属软件的开发和应用,已经方便并加快了蛋白质分子核磁共振谱峰的归属进程.然而,对蛋白质核磁共振研究领域的新手来说,因为缺乏对蛋白质分子的核磁共振谱峰特性的系统认识而可能发生对自动归属结果的错误指认或指认不完全,从而导致蛋白质结构解析的错误或偏差.该文针对蛋白质分子中的核磁共振谱峰特性,比如同位素效应和立体异构等,结合具体的蛋白质分子的核磁共振实验图谱,进行了较为详尽的论述,期望对从事蛋白质核磁共振的研究者在理解蛋白质分子的核磁共振谱峰特性及其归属方面有所裨益.展开更多
Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesi...Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.展开更多
文摘尽可能完全、准确地归属蛋白质分子的核磁共振(Nuclear Magnetic Resonance,NMR)谱峰,是解析可信赖、高质量的蛋白质三维空间溶液结构的首要条件.自动归属软件的开发和应用,已经方便并加快了蛋白质分子核磁共振谱峰的归属进程.然而,对蛋白质核磁共振研究领域的新手来说,因为缺乏对蛋白质分子的核磁共振谱峰特性的系统认识而可能发生对自动归属结果的错误指认或指认不完全,从而导致蛋白质结构解析的错误或偏差.该文针对蛋白质分子中的核磁共振谱峰特性,比如同位素效应和立体异构等,结合具体的蛋白质分子的核磁共振实验图谱,进行了较为详尽的论述,期望对从事蛋白质核磁共振的研究者在理解蛋白质分子的核磁共振谱峰特性及其归属方面有所裨益.
基金Project(42076043) supported by the National Natural Science Foundation of ChinaProject(ZR2023ZD31) supported by the Major Basic Research Project of Natural Science Foundation of Shandong Province,ChinaProject(2023VEA0007) supported by the Chinese Academy of Sciences President’s International Fellowship Initiative。
文摘Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.