Cover image

Cover In flowering plants, a thiamine pyrophosphate (TPP)-binding riboswitch regulates gene expression by directing alternative splicing within the 3′ untranslated region of the Arabidopsis THIAMINE C SYNTHASE gene (AtTHIC). Shown here is a picture of an Arabidopsis flower, alongside a structure model for the riboswitch forming two parallel helices binding a TPP molecule. A pocket in one sensor helix accommodates the pyrimidine ring (mixed orange and gray atoms) while the second helix binds the pyrophosphate (mixed yellow and green atoms). (For details see Bocobza et al., p. 2874.)