Kawabata Mai, Kawashima Kentaro, Mutsuro-Aoki Hiromi, Ando Tadashi, Umehara Takuya, Tamura Koji
Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
Department of Applied Electronics, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan.
Life (Basel). 2022 Apr 12;12(4):573. doi: 10.3390/life12040573.
The peptidyl transferase center (PTC) in the ribosome is composed of two symmetrically arranged tRNA-like units that contribute to peptide bond formation. We prepared units of the PTC components with putative tRNA-like structure and attempted to obtain peptide bond formation between aminoacyl-minihelices (primordial tRNAs, the structures composed of a coaxial stack of the acceptor stem on the T-stem of tRNA). One of the components of the PTC, P1c2 (74-mer), formed a dimer and a peptide bond was formed between two aminoacyl-minihelices tethered by the dimeric P1c2. Peptide synthesis depended on both the existence of the dimeric P1c2 and the sequence complementarity between the ACCA-3' sequence of the minihelix. Thus, the tRNA-like structures derived from the PTC could have originated as a scaffold of aminoacyl-minihelices for peptide bond formation through an interaction of the CCA sequence of minihelices. Moreover, with the same origin, some would have evolved to constitute the present PTC of the ribosome, and others to function as present tRNAs.
核糖体中的肽基转移酶中心（PTC）由两个对称排列的类似tRNA的单元组成，这些单元有助于肽键的形成。我们制备了具有假定类似tRNA结构的PTC组件单元，并试图在氨酰基小螺旋（原始tRNA，由tRNA的T茎上的受体茎同轴堆叠组成的结构）之间实现肽键形成。PTC的一个组件P1c2（74聚体）形成了二聚体，并且在由二聚体P1c2连接的两个氨酰基小螺旋之间形成了肽键。肽合成既依赖于二聚体P1c2的存在，也依赖于小螺旋ACCA-3'序列之间的序列互补性。因此，源自PTC的类似tRNA的结构可能最初是作为氨酰基小螺旋的支架，通过小螺旋的CCA序列相互作用来形成肽键。此外，出于相同的起源，一些结构会进化为构成核糖体目前的PTC，而另一些则会进化为发挥目前tRNA的功能。
