铁调蛋白的功能及应用前景

铁调蛋白不仅可以调节微生物细胞内与金属内稳态直接相关的基因表达,还可以调节细胞代谢以减少细胞对供应短缺的金属的需求。目前,对铁调蛋白的研究已有一定的成果,部分铁调蛋白的结合位点的氨基酸残基及调节机制都被确定。本综述总结了铁调蛋白的金属转录调节因子,介绍了关于铁调蛋白基因表达机制的研究现状以及铁调蛋白在不同领域的功能,此外还介绍了最新铁调蛋白调控微生物细胞金属响应结合位点方面的最新进展,以及在生物冶金与其他方面的应用前景。     

De Novo synthesis of DNA-like molecules by polynucleotide phosphorylase in vitro

In the presence of Mg²⁺ ions, polynucleotide phosphorylase (PNPase, EC 2.7.7.8) is known to synthesize RNA-like polymers using ribonucleoside-5′-diphosphate (NDP) substrates but to be unable to utilize deoxyribonucleoside substrates. Our experiments show that when MgCl₂ is replaced by FeCl₃, PNPase becomes able to synthesize deoxyheteropolymers using deoxyribonucleoside-5′-diphosphates (dNDPs). The deoxyheteropolymer formed from the four dNDPs is degraded by pancreatic DNase, but not by RNase, and is readily used as a template by DNA-dependent DNA polymerase. Synthesis of this DNA-like polymer is accomplished de novo without the help of any primer or preexisting template. What is more, dA/dG and dC/dT ratios of polymers synthesized by different bacterial PNPases closely match ratios found in DNA of the bacterial species the enzyme came from.