The long D-stem of the selenocysteine tRNA provides resilience at the expense of maximal function

Abstract

Background: The selenocysteine tRNA (tRNASec) has a uniquely long D-stem containing 6 base pairs. Results: The extended D-stem is not essential for function but is required for stability. Conclusion: Enhanced secondary structure in selenocysteine tRNA compensates for the absence of canonical tertiary interactions. Significance: The flexibility due to the absence of tertiary interactions is required for tRNASec function, whereas the enhanced secondary structure compensates for the decreased stability. Copyright © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.