Dramatic improvement of crystals of large RNAs by cation replacement and dehydration.

ABSTRACT: Compared to globular proteins, RNAs with complex 3D folds are characterized by poorly differentiated molecular surfaces dominated by backbone phosphates, sparse tertiary contacts stabilizing global architecture, and conformational flexibility. The resulting generally poor order of crystals of large RNAs and their complexes frequently hampers crystallographic structure determination. We describe and rationalize a postcrystallization treatment strategy that exploits the importance of solvation and counterions for RNA folding. Replacement of Li(+) and Mg(2+) needed for growth of crystals of a tRNA-riboswitch-protein complex with Sr(2+), coupled with dehydration, dramatically improved the resolution limit (8.5-3.2 Å) and data quality, enabling structure determination. The soft Sr(2+) ion forms

SUBMITTER: Zhang J 

PROVIDER: S-EPMC4177851 | biostudies-literature | 2014 Sep

REPOSITORIES: biostudies-literature