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Publication Abstract from PubMed

The extant complex proteins must have evolved from ancient short and simple ancestors. The double-psi beta-barrel (DPBB) is one of the oldest protein folds and conserved in various fundamental enzymes, such as the core domain of RNA polymerase. Here, by reverse engineering a modern DPBB domain, we reconstructed its plausible evolutionary pathway started by "interlacing homodimerization" of a half-size peptide, followed by gene duplication and fusion. Furthermore, by simplifying the amino acid repertoire of the peptide, we successfully created the DPBB fold with only seven amino acid types (Ala, Asp, Glu, Gly, Lys, Arg, and Val), which can be coded by only GNN and ARR (R = A or G) codons in the modern translation system. Thus, the DPBB fold could have been materialized by the early translation system and genetic code.

Seven Amino Acid Types Suffice to Create the Core Fold of RNA Polymerase.,Yagi S, Padhi AK, Vucinic J, Barbe S, Schiex T, Nakagawa R, Simoncini D, Zhang KYJ, Tagami S J Am Chem Soc. 2021 Oct 6;143(39):15998-16006. doi: 10.1021/jacs.1c05367. Epub, 2021 Sep 24. PMID:34559526^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.