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  1. Aug 2025
  2. Jul 2025
    1. We then evolved the deletion strain and observed that the genetic adaptation was recurrently based on a strategic mutation that changed the anticodon of other tRNA genes to match that of the deleted one.

      This is a key finding. It highlights how a single point mutation in an anticodon can functionally replace a lost tRNA, emphasizing the adaptability of the translational machinery.

    1. t5+1 could assemble these into αβ+ and γδε+ fragments, guided only by partially overlapping ‘−’ strands (Figure 6b, Figure 6—figure supplement 1). Through non-covalent association (Vaish et al., 2003; Mutschler et al., 2015), the ribozyme-synthesised αβ+ and γδε+ fragments spontaneously reconstituted a new catalytically active triplet polymerase ribozyme (with in vitro transcribed type 1 RNA)

      The ribozyme can build copies of parts of itself and put them together like puzzle pieces to regenerate function. That’s basically modular self-replication, which I thought only synthetic biology was capable of.

    2. RNA catalysis is dependent upon RNA folding, and this yields structures that can block replication of such RNAs. To address this apparent paradox, we have re-examined the building blocks used for RNA replication.

      This blew my mind, RNA has to fold into specific shapes to work like a ribozyme, but those same shapes make it harder to copy. It’s like building a key that locks itself.

    3. Although still inefficient, the fact that the nascent activity of the 0core ribozyme could already copy templates that had confounded an established RPR encouraged us to continue to seek improved triplet polymerase ribozymes to leverage this substrate behaviour.

      This early success gave the researchers a good reason to keep pushing forward, since it hinted that triplet-based RNA replication might help overcome a key obstacle in the field.

    4. he strong inhibitory role of this central feature of RNA leads to an antagonism between the degree to which an RNA sequence is able to fold into a defined three-dimensional structure to encode function (such as catalysis) and the ease with which it can be replicated (Boza et al., 2014).

      This "structure vs. replication" tradeoff is a bigger deal because it may have made it harder for life to get started using RNA as both the genetic material and the machinery for replication.

    5. Yet, although ribozymes can be made to copy straight RNA templates this way, folded RNA templates – including the replicase ribozyme itself – impede copying. In this apparent paradox, a ribozyme needs to fold to copy RNA, but when folded, is itself copied poorly. Here, Attwater et al. wondered if choosing different building blocks might overcome this contradiction.

      I think this presents a contradiction, that the structure hat enables function also hinders duplication. However, the sentence introduces a key barrier that the research seeks to address.