Beaufils Damien, Jepaul Sandra, Liu Ziwei, Boiteau Laurent, Pascal Robert
Institut des Biomolécules Max Mousseron, UMR 5247, CNRS - University of Montpellier, DSBC, CC17006, Place E. Bataillon, 34095, Montpellier Cedex 5, France.
Orig Life Evol Biosph. 2016 Mar;46(1):19-30. doi: 10.1007/s11084-015-9455-0. Epub 2015 Jul 24.
The activation of dipeptides was studied in the perspective of the abiotic formation of oligopeptides of significant length as a requirement for secondary structure formation. The formation of piperazin-2,5-diones (DKP), previously considered as a dead end when activating free dipeptides, was shown in this work to be efficiently suppressed when using strong activating agents (e.g., carbodiimides). This behaviour was explained by the fast formation of a 5(4H)-oxazolone intermediate at a rate that exceeds the time scale of the rotation of the peptide bond from the predominant trans-conformation into the cis-isomer required for DKP formation. No DKP was observed when using strong activating agents whereas phosphate mixed anhydrides or moderately activated esters were observed to predominantly yield DKP. The DKP side-reaction no longer constitutes a drawback for the C-terminus elongation of peptides. These results are considered as additional evidence that pathways involving strong activation are required to drive the emergence of living entities rather than close to equilibrium processes.
从形成具有显著长度的寡肽的非生物过程角度出发，研究了二肽的活化，这是二级结构形成的必要条件。在这项工作中表明，当使用强活化剂（如碳二亚胺）时，先前被认为在活化游离二肽时是死路的哌嗪 - 2,5 - 二酮（DKP）的形成能被有效抑制。这种行为的解释是，5(4H)-恶唑酮中间体快速形成，其速率超过了肽键从主要的反式构象旋转到形成DKP所需的顺式异构体的时间尺度。使用强活化剂时未观察到DKP，而磷酸混合酸酐或适度活化的酯则主要产生DKP。DKP副反应不再是肽C末端延伸的一个缺点。这些结果被视为额外的证据，表明需要涉及强活化的途径来推动生命实体的出现，而不是接近平衡的过程。
