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Aldehydes generate N-alkylated-aa-tRNA adducts TLC showing modification on L-and D-Tyr-tRNA Tyr by A) formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, isovaleraldehyde, decanal and B) MG (AMP: adenine mono phosphate which corresponds to free tRNA; whereas Tyr-AMP and Modified-Tyr-AMP corresponds to unmodified and modified Tyr-tRNA Tyr ). Mass spectra showing C) DPhe-tRNA Phe , D) formaldehyde modified D-Phe-tRNA Phe E) propionaldehyde modified D-Phe-tRNA Phe F) Butyraldehyde modified D-Phe-tRNA Phe G) MG modified D-Phe-tRNA Phe . H) Graph showing the effect of increasing chain length of aldehyde on modification propensity with aa-tRNA at two different concentrations of various aldehydes. Effect of I) formaldehyde, and J) MG modification on stability of ester linkage in D-aa-tRNA under alkaline conditions.
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Land plants have developed intricate metabolic pathways which involve production of reactive aldehydes and its detoxification to survive harsh terrestrial environments. Aldehydes, being an integral part of carbon metabolism, energy generation and signalling pathways, are ingrained in plant physiology. Here, we show that physiologically abundantly p...
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... levels of formaldehyde and MG leads to toxicity in various life forms like bacteria 18 and mammals 9 ,19 ,20 . However, archaea and plants possess these aldehydes in extremely high amounts (>25-fold) ( Figure: S1A ), yet there is no evidence of toxicity 3 ,21 - 29 . This suggests that both archaea and plants have evolved specialised protective mechanisms against toxic aldehyde flux. ...
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... have shown that acetaldehyde irreversibly modifies D-aminoacyl-tRNAs (D-aa-tRNA) and only DTD2 can recycle the modified D-aa-tRNAs thus replenishing the free tRNA pool for further translation 40 . Like acetaldehyde, elevated aldehyde spectrum ( Figure: S1A) in plants and archaea pose a threat to the translation machinery. The unique presence of DTD2 in organisms with elevated aldehyde spectrum (plants and archaea) and its indispensable role in acetaldehyde tolerance prompted us to investigate the role of archaeal DTD2 in safeguarding translation apparatus of plants from various physiologically abundant toxic aldehydes. ...
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... mass change from formaldehyde, propionaldehyde, butyraldehyde and MG modification correspond to a methyl, propyl, butyl and acetonyl group, respectively ( Figure: 1B-G ). Tandem fragmentation (MS 2 ) of aldehyde-modified D-aa-tRNAs showed that all the aldehydes selectively modify only the amino group of amino acids in D-aa-tRNAs ( Figure: S1C-G ). Interestingly, upon a comparison of modification strength, the propensity of modification decreased with increase in the aldehyde chain length with no detectable modification on decanal treated aa-tRNAs ( Figure: 1A, 1H ). ...
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... fragmentation (MS 2 ) of aldehyde-modified D-aa-tRNAs showed that all the aldehydes selectively modify only the amino group of amino acids in D-aa-tRNAs ( Figure: S1C-G ). Interestingly, upon a comparison of modification strength, the propensity of modification decreased with increase in the aldehyde chain length with no detectable modification on decanal treated aa-tRNAs ( Figure: 1A, 1H ). The chemical reactivity of aldehyde is dictated by its electrophilicity 42 . ...
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... was activated by exchanging the GDP with GTP. Activated EF-Tu protected L-aa-tRNAs from RNase ( Figure: S1I ). Next, we generated the ternary complex of activated EF-Tu and aa-tRNAs and incubated with formaldehyde. ...
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... mixture was quenched at multiple time points and modification was assessed using TLC. It has been seen that activated EF-Tu protected L-aa-tRNAs from smallest aldehyde suggesting that EF-Tu is a dedicated protector of L-aa-tRNAs from all the cellular metabolites ( Figure: S1J ). However, the lower affinity of D-aa-tRNAs with EF-Tu results in their modification under aldehyde flux. ...
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... suggests that DTD2 exerts its protection till propionaldehyde with a significant preference for methylglyoxal and formaldehyde modified D-aa-tRNAs. It is worth noting that the physiological levels of higher chain length aldehydes are comparatively much lesser in plants and archaea ( Figure: S1A ), indicating the coevolution of DTD2 activity with the presence of toxic aldehydes. Even though both MG and propionaldehyde generate a 3-carbon chain modification, DTD2 showed ∼100-fold higher activity on MG-modified D-aa-tRNAs ( Figure: 2B-C , 2F-G , 2M ). ...
