Title: On an RNA-membrane protogenome Show Chinese title

Title: 关于RNA-膜原型基因组

Abstract: Selected ribonucleotide sequences bind well to zwitterionic phospholipid bilayer membranes, though randomized RNAs do not. There are no evident repeated sequences in selected membrane binding RNAs. This implies small and varied motifs responsible for membrane affinity. Such subsequences have been partially defined. Bound RNAs require divalents like Mg2+ and/or Ca2+, preferring more ordered phospholipids: gel, ripple or rafted membranes, in that order. RNAs also bind and stabilize bilayers that are bent or sharply deformed. In contrast, RNA binding without divalents extends to negatively charged membranes formed from simpler anionic phospholipids, and to plausibly prebiotic fatty acid bilayers. RNA-membranes also retain RNA function, such as base pairing, passive transport of tryptophan, specific affinity for peptide side chains, like arginine, and catalysis by ribozymic ligase. Multiple membrane-bound RNAs with biochemical functions, linked by specific base-pairing are readily constructed. Given these experimental facts, genetic effects seem plausible. RNA functions often reside in few nucleotides, and are easily joined in a small RNA. Base-paired groups of these can evolve to be purposeful, joining related RNA functions. Such RNA groups permit complex genome functions, but require only replication of short RNAs. RNA-membranes facilitate accurate RNA segregation at cell division, and quickly evolve by appending new base-paired functions. Thus, ancient RNA-membranes could act as a protogenome, supporting orderly encoded RNA expression, inheritance and evolution before DNA and the DNA genome. Show Chinese abstract

Abstract: 选择的核糖核酸序列能很好地结合到两性离子磷脂双层膜上，而随机化的RNA则不能。 在所选的膜结合RNA中没有明显的重复序列。 这意味着负责膜亲和力的小而多样的基序。 这些亚序列已被部分定义。 结合的RNA需要二价阳离子，如Mg²⁺和/或Ca²⁺，并且更倾向于有序的磷脂：凝胶状、波纹状或筏状膜，按此顺序。 RNA还能结合并稳定弯曲或严重变形的双层膜。 相比之下，在没有二价阳离子的情况下，RNA结合可以扩展到由简单阴离子磷脂形成的带负电荷的膜，以及可能的前生物脂肪酸双层膜。 RNA-膜还能保留RNA的功能，如碱基配对、色氨酸的被动运输、对肽侧链（如精氨酸）的特异性亲和力以及核酶连接酶的催化作用。 具有生化功能的多个膜结合RNA可以通过特定碱基配对轻松构建。 鉴于这些实验事实，遗传效应似乎是合理的。 RNA功能通常存在于少数几个核苷酸中，并且容易在小RNA中结合。 这些碱基配对组可以进化为有目的的结构，结合相关的RNA功能。 这样的RNA组允许复杂的基因组功能，但只需要短RNA的复制。 RNA-膜有助于细胞分裂时RNA的准确分离，并通过添加新的碱基配对功能迅速进化。 因此，古代RNA-膜可以充当原型基因组，在DNA和DNA基因组之前支持有序编码的RNA表达、遗传和进化。