REDUCED AMINO ACID SET PROTEINS SUGGEST A ROLE OF PREBIOTIC AMINO ACIDS IN PRIMITIVE PROTEIN SYNTHESIS

• Shibue Rei

  Faculty of Human Sciences, Waseda University

• Akanuma Satoshi

  Faculty of Human Sciences, Waseda University

Abstract

Contemporary organisms commonly use the genetically encoded 20 amino acids to synthesize proteins. However, earlier protein synthesis was plausibly much simpler and utilized a subset of the standard proteinogenic amino acids. We reconstructed ancestral nucleoside diphosphate kinases (NDKs) by combining the computational inference of ancestral sequence and a whole gene synthesis technique. One of the reconstructed NDKs, Arc1, is an extremely thermally stable protein with the unfolding midpoint temperature of 114℃ and the magnitude of its specific activity is comparable with those of extant NDK. Arc1 lacks cysteine and therefore consists of 19 amino acid letters. To address simpler constituents for primitive proteins, we comprehensively reduce the size of the amino acid alphabet in Arc1 to reduced sets. We found that many but not all of the reduced-set amino acids were consistent with those plausibly abundant in primitive environment. We also found that the remaining inconsistent amino acids were important for activity but not for stability. Our results are compatible with the hypothesis that amino acids available in the prebiotic environment were first used for creating stable protein structures and their functions were later improved by recruiting other amino acids.

Journal

• Viva Origino

  Viva Origino 46 (3), 4-, 2018

  The Society for the Study of the Origin and Evolution of Life Japan

Keywords

• Ancestral protein
• origin of life
• origin of translation
• primitive amino acid repertoire
• primitive proteins
• protein simplification
• reduced amino acid alphabet

Details

• CRID: 1390853022611920640
• NII Article ID: 130008116896
• DOI: 10.50968/vivaorigino.46_4
• ISSN: 13466933
• ISSN: 09104003
• Text Lang: ja
• Data Source:
  • JaLC
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Allowed