Figure 1.

Statistics for nucleic acid versus protein structures. (a) Pie chart describing the percentage of X-ray structures solved containing different types of macromolecules. Nucleic acids are significantly underrepresented relative to proteins. Statistics were calculated from the PDB as of 19 February 2013. (b) Distribution of coding versus noncoding transcripts in the cell, as derived from genomic data analysis (Washietl et al., 2007 ▶; The Encode Project Consortium, 2012 ▶). An increasingly large number of noncoding elements have been shown to possess distinct tertiary structures; therefore, the quantity and the variety of nucleic acid crystallography targets are rapidly increasing.