SH – Department of Biochemistry and Biophysics – UNC School of Medicine

Figure 1. The reflexivity of AARS genes and the challenges of understanding its origin. The figure illustrates three main challenges. (I) We must construct a bidirectional gene (salmon background) that uses a minimal amino acid alphabet to encode ancestral AARS from Classes I and II on opposite strands. Polypeptide and nucleic acid sequences have directions indicated by (N,C) and (5’,3’). The genes are sequences of codons (colored ellipses) and use only two types of amino acids, A and B. (II) We must show that both coded proteins (I and II) fold into active assignment catalysts that recognize both amino acid and tRNA (colored letters, ellipses in cavities), producing (mostly) aminoacyl-tRNAs with correct amino acids and anticodons. (III) We have to show that the aminoacylated RNAs can assemble onto messenger RNAs (I) and (II), transcribed from the bidirectional gene (reversed dashed arrows).

Structural biology research and the origins of genetic coding

March 18, 2024

Charles W. Carter, Jr, Department of Biochemistry and Biophysics, University of North Carolina Chapel Hill, reviews the ways that recent research in Structural Biology, Biochemistry, Molecular Biology, and Phylogenetics have opened the origins of genetic coding to experimental study and their important implications.

Figure 1. Elements of the operational RNA code in the tRNA acceptor stem. A. Bases in the tRNA acceptor stem encode two aspects of amino acid physical chemistry—size and polarity—that determine protein folding. B. Acceptor stem bases preceded the anticodon stem-loop and code other properties. C. The oldest parts of Class I and II AARS could already discriminate between both amino acid and RNA substrates (6) .

tRNA: The operational RNA code and protein folding

January 12, 2024

Charles W. Carter, Jr., from the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, relates molecular recognition used in genetic coding to structures of aminoacyl-tRNA synthetases and their cognate tRNAs.

Dna test infographic. Genome sequence map.

Chicken or egg? Pursuing historical context

October 19, 2023

Charles W Carter Jr, Department of Biochemistry & Biophysics, University of North Carolina at Chapel Hill, explores prebiotic processes from the historical context enabling the emergence of translation.

DNA sequencing gel run science and data genomic genetic analysis background abstract pattern.

AARS urzymes: Experimental biochemistry to map genetic coding

June 29, 2023

Dr Charlie Carter from the University of North Carolina at Chapel Hill explores how advances in enzymology and phylogenetics enable biochemical measurements that could map the ancestral development of genetic coding.

DNA helix colorful genes chromosomes DNA sequence, DNA structure with glow. Science concept background 3d rendering

Genetic coding: Roots of genetic readout in nucleic acid structural duality

March 30, 2023

Charles W. Carter, Jr, from the Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill explores the roots of genetic readout in the inherent structural duality of DNA and how genetic coding expanded its potential, enabling life to emerge.

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