Department of Biochemistry, The University of Texas Health Science Center, San Antonio, TX 78229, USA.
Viruses. 2011 Jul;3(7):1249-80. doi: 10.3390/v3071249. Epub 2011 Jul 20.
I present a hypothesis that begins with the proposal that abiotic ancestors of phage RNA and DNA packaging systems (and cells) include mobile shells with an internal, molecule-transporting cavity. The foundations of this hypothesis include the conjecture that current nucleic acid packaging systems have imprints from abiotic ancestors. The abiotic shells (1) initially imbibe and later also bind and transport organic molecules, thereby providing a means for producing molecular interactions that are links in the chain of events that produces ancestors to the first molecules that are both information carrying and enzymatically active, and (2) are subsequently scaffolds on which proteins assemble to form ancestors common to both shells of viral capsids and cell membranes. Emergence of cells occurs via aggregation and merger of shells and internal contents. The hypothesis continues by using proposed imprints of abiotic and biotic ancestors to deduce an ancestral thermal ratchet-based DNA packaging motor that subsequently evolves to integrate a DNA packaging ATPase that provides a power stroke.
我提出了一个假说，该假说从以下假设开始：噬菌体 RNA 和 DNA 包装系统（和细胞）的无生命祖先包括带有内部分子运输腔的可移动外壳。该假说的基础包括这样一个猜想，即当前的核酸包装系统具有无生命祖先的痕迹。无生命的外壳（1）最初吸收，后来也结合和运输有机分子，从而提供了一种产生分子相互作用的手段，这些相互作用是产生既携带信息又具有酶活性的第一批分子的事件链中的环节，并且（2）随后成为蛋白质组装的支架，形成病毒衣壳和细胞膜的共同祖先。通过外壳和内部内容的聚集和合并，细胞出现。该假说接着利用无生命和有生命祖先的拟议痕迹来推断出基于热棘轮的祖先 DNA 包装马达，随后该马达进化为整合 DNA 包装 ATP 酶，提供动力冲程。
