Selenocysteine: Difference between revisions
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==Structure and Synthesis== | ==Structure and Synthesis== | ||
Cysteine (Cys) has a sulfur-containing side chain '''-CH<sub>2</sub>-SH'''. In selenocysteine, the sulfur is replaced with selenium, making the side chain''' -CH<sub>2</sub>-SeH'''. | |||
Cysteine (Cys) has a sulfur-containing side chain '''-CH<sub>2</sub>-SH'''. In selenocysteine, the sulfur is replaced with selenium, making the side chain''' -CH<sub>2</sub>-SeH'''. However, as explained below, Sec is not synthesized from Cys, but rather from Ser (sidechain '''-CH<sub>2</sub>-OH, by the replacement of oxygen with selenium. | |||
Sec differs from the [[Amino Acids|20 standard amino acids]] because, in all domains of life, it lacks its own tRNA synthetase, and is synthesized from Ser covalently linked to tRNA<sup>Sec</sup>. | Sec differs from the [[Amino Acids|20 standard amino acids]] because, in all domains of life, it lacks its own tRNA synthetase, and is synthesized from Ser covalently linked to tRNA<sup>Sec</sup>. | ||
The structure of the complex that converts Ser-tRNA<sup>Sec</sup> to Sec-tRNA<sup>Sec</sup> was solved in 2009<ref name='Palioura'>PMID: 19608919</ref>. | |||
==Notes and References== | ==Notes and References== | ||
<references /> | <references /> | ||
