Peptide nucleic acids rather than RNA may have been the first genetic molecule
Peptide nucleic acids rather than RNA may have been the first genetic molecule
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DOI：
10.1073/pnas.97.8.3868
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发表时间：
2000-04-11
影响因子：
11.1
通讯作者：
Miller, SL
中科院分区：
文献类型：
--
作者：
Nelson, KE;Levy, M;Miller, SL
目前认为RNA是第一种遗传物质的想法存在许多问题。目前还没有合理的益生元过程被证明可以产生核苷或核苷酸，或者进行有效的双向非酶复制。肽核酸（PNA）是一种很有前途的RNA前体，由N-（2-氨乙基）甘氨酸（AEG）和腺嘌呤、尿嘧啶、鸟嘌呤和胞嘧啶-N-乙酸组成。然而，PNA尚未被证明是益生元。我们在这里表明，AEG是直接从CH 4，N-2，NH 3，和H 2 O放电反应。放电也产生乙二胺，如NH 4CN聚合。AEG是由具有乙二胺的稳健Strecker合成法生产的。在甘氨酸存在下的NH 4CN聚合导致腺嘌呤和鸟嘌呤-Ng-乙酸，并且从氰基乙醛与乙内酰脲酸而不是尿素的反应中以高产率产生胞嘧啶和尿嘧啶-N-1-乙酸。初步的实验表明，AEC可以在100摄氏度下快速分解，得到PNA的多肽骨架。合成PNA组分的容易性和AEG聚合的可能性加强了PNA可能是第一个遗传物质的可能性。
Numerous problems exist with the current thinking of RNA as the first genetic material. No plausible prebiotic processes have yet been demonstrated to produce the nucleosides or nucleotides or for efficient two-way nonenzymatic replication. Peptide nucleic acid (PNA) is a promising precursor to RNA, consisting of N-(2-aminoethyl)glycine (AEG) and the adenine, uracil, guanine, and cytosine-N-acetic acids. However, PNA has not yet been demonstrated to be prebiotic. We show here that AEG is produced directly in electric discharge reactions from CH4, N-2, NH3, and H2O. Electric discharges also produce ethylenediamine, as do NH4CN polymerizations. AEG is produced from the robust Strecker synthesis with ethylenediamine. The NH4CN polymerization in the presence of glycine leads to the adenine and guanine-Ng-acetic acids, and the cytosine and uracil-N-1-acetic acids are produced in high yield from the reaction of cyanoacetaldehyde with hydantoic acid, rather than urea. Preliminary experiments suggest that AEC may polymerize rapidly at 100 degrees C to give the polypeptide backbone of PNA. The ease of synthesis of the components of PNA and possibility of polymerization of AEG reinforce the possibility that PNA may have been the first genetic material.