Definition of "selenocysteine" [selenocysteine]

• A naturally-occurring amino acid, present in several enzymes, whose structure is that of cysteine but with the sulfur atom replaced by one of selenium (noun)

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• "So it will need to be consistent not with merely the ribosome and the bacterial flagella, but also the octopus's eye, the panda's thumb, and the jerry-rigged way that selenocysteine is kluged into the genetic code."
• "The awkward way in which selenocysteine is kluged into the genetic code (which is not unique to Tetrahymena; we do it too), sharing a termination codon instead of having one to itself seems like a good example of a molecular "panda's thumb," reflecting the inherent difficulty of a late addition to the frozen accident of the genetic code."
• "The third termination codon, UGA, does signal for termination, but can also be used in a context-dependent manner (depending on RNA structure) to code the amino acid, selenocysteine."