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Figure 2 | Biology Direct

Figure 2

From: The Rodin-Ohno hypothesis that two enzyme superfamilies descended from one ancestral gene: an unlikely scenario for the origins of translation that will not be dismissed

Figure 2

Detailed comparison between active sites of Class I and Class II aminoacyl-tRNA synthetases. Substrate binding sites for ATP and amino acid are buried in Class I, and much closer to the surface in Class II enzymes. The color of the active-site spheres illustrates that conserved active-site residues that motivated Rodin and Ohno to advance their sense/antisense coding hypothesis are drawn exclusively from the set of substrates activated by the other class. The median transfer free energy from water to cyclohexane is favorable for Class I substrates and unfavorable for Class II substrates.

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Biology Direct

ISSN: 1745-6150

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