The Long D-stem of the Selenocysteine tRNA Provides Resilience at the Expense of Maximal Function

Ishii, Tetsu; Kotlova, Natalia; Tapsoba, Franck; Steinberg, Sergey V.

doi:10.1074/jbc.m112.434704

Cited by 6 publications

(4 citation statements)

References 20 publications

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“…Increasing β-lactam antibiotic concentration exerts selective pressure for increased production of NMC-A β-lactamase, which in turn requires an increase in selenocysteine incorporation. Elevated temperature reduces tRNA Sec stability, which in turn decreases selenocysteine incorporation 12 , and might result in evolution of more stable or more active selenocysteine incorporation machinery.…”

Section: Resultsmentioning

confidence: 99%

Custom selenoprotein production enabled by laboratory evolution of recoded bacterial strains

et al. 2018

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Incorporation of the rare amino acid selenocysteine to form diselenide bonds can improve stability and function of synthetic peptide therapeutics. However, application of this approach to recombinant proteins has been hampered by heterogeneous incorporation, low selenoprotein yields, and poor fitness of bacterial producer strains. We report the evolution of recoded E. coli strains with improved fitness that are superior hosts for recombinant selenoprotein production. We apply an engineered β-lactamase containing an essential diselenide bond to enforce selenocysteine dependence during continuous evolution of recoded E. coli strains. Evolved strains maintain an expanded genetic code indefinitely. We engineer a fluorescent reporter to quantify selenocysteine incorporation in vivo and show complete decoding of UAG codons as selenocysteine. Replacement of native, labile disulfide bonds in antibody fragments with diselenide bonds vastly improves resistance to reducing conditions. Highly seleno-competent bacterial strains enable industrial-scale selenoprotein expression and unique diselenide architecture, advancing our ability to customize the selenoproteome.

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Section: Resultsmentioning

confidence: 99%

Custom selenoprotein production enabled by laboratory evolution of recoded bacterial strains

et al. 2018

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“…Further studies found that the interaction of SelA is not sequence-based but rather structural. The presence of the 5 th and 6 th bp in the D-arm of tRNA Sec (regardless of sequence) had a positive impact on its activity (Ishii et al, 2013).…”

Section: Introductionmentioning

confidence: 97%

Naturally Occurring tRNAs With Non-canonical Structures

2020

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Transfer RNA (tRNA) is the central molecule in genetically encoded protein synthesis. Most tRNA species were found to be very similar in structure: the well-known cloverleaf secondary structure and L-shaped tertiary structure. Furthermore, the length of the acceptor arm, T-arm, and anticodon arm were found to be closely conserved. Later research discovered naturally occurring, active tRNAs that did not fit the established 'canonical' tRNA structure. This review discusses the non-canonical structures of some well-characterized natural tRNA species and describes how these structures relate to their role in translation. Additionally, we highlight some newly discovered tRNAs in which the structure-function relationship is not yet fully understood.

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“…In addition, the crystal structure of tRNA [Ser]Sec demonstrated that the unusually long D stem containing 6 bp in this tRNA does not interact with the variable arm, resulting in an open cavity instead of the tertiary hydrophobic core (156). Two additional base pairs in the D stem of tRNA [Ser]Sec have been shown to be required for formation of enhanced secondary structure that compensates for the absence of canonical tertiary interactions (154).…”

Section: Sec Biosynthesismentioning

confidence: 99%

Selenoproteins: Molecular Pathways and Physiological Roles

Labunskyy

Hatfield

Gladyshev³

2014

Physiological Reviews

1,063

835

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Selenium is an essential micronutrient with important functions in human health and relevance to several pathophysiological conditions. The biological effects of selenium are largely mediated by selenium-containing proteins (selenoproteins) that are present in all three domains of life. Although selenoproteins represent diverse molecular pathways and biological functions, all these proteins contain at least one selenocysteine (Sec), a seleniumcontaining amino acid, and most serve oxidoreductase functions. Sec is cotranslationally inserted into nascent polypeptide chains in response to the UGA codon, whose normal function is to terminate translation. To decode UGA as Sec, organisms evolved the Sec insertion machinery that allows incorporation of this amino acid at specific UGA codons in a process requiring a cis-acting Sec insertion sequence (SECIS) element. Although the basic mechanisms of Sec synthesis and insertion into proteins in both prokaryotes and eukaryotes have been studied in great detail, the identity and functions of many selenoproteins remain largely unknown. In the last decade, there has been significant progress in characterizing selenoproteins and selenoproteomes and understanding their physiological functions. We discuss current knowledge about how these unique proteins perform their functions at the molecular level and highlight new insights into the roles that selenoproteins play in human health.

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The Long D-stem of the Selenocysteine tRNA Provides Resilience at the Expense of Maximal Function

Cited by 6 publications

References 20 publications

Custom selenoprotein production enabled by laboratory evolution of recoded bacterial strains

Custom selenoprotein production enabled by laboratory evolution of recoded bacterial strains

Naturally Occurring tRNAs With Non-canonical Structures

Selenoproteins: Molecular Pathways and Physiological Roles

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