In the dark, COP1, an E3 ligase, ubiquitinates HY5.

TLS Online TPP Program

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#Unit 3. Fundamental Processes

Some microorganisms that lack AsnRS use a similar transamidation pathway for the synthesis of Asn–tRNAAsn from Asp–tRNAAsn.

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#Unit 3. Fundamental Processes

The translation machinery relies on the high fidelity of the aminoacyl-tRNA synthetases to ensure the accurate decoding of each mRNA.

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#Unit 3. Fundamental Processes

Certain archaebacteria lack a gene for CysRS. In these cells, Cys–tRNACys is produced by a ProRS (called ProCysRS).

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#Unit 3. Fundamental Processes

Certain proteins, such as the enzymes glutathione peroxidase and formate dehydrogenase, contain an unusual amino acid called selenocysteine, which is part of the catalytic center of the enzymes.

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#Unit 3. Fundamental Processes

Human proteome contains 25 selenoproteins. Selenocysteine, sometimes called the “twenty-first amino acid,”

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#Id: 3658

#Unit 3. Fundamental Processes

Selenocysteine is incorporated into proteins with the aid of a tRNA that interprets the UGA Stop codon as a Sec codon. tRNASec is initially charged with serine in a reaction catalyzed by the same SerRS that charges tRNASer.