Molecular Structure of the mRNA Export Factor Gle1 from Debaryomyces hansenii

Gle1 functions as a regulator of Dbp5, a DEAD-box-containing RNA helicase that is a component of the nuclear pore complex. In association with Gle1 and inositol hexakisphosphate (IP6), ADP-bound Dbp5 facilitates the release of RNA. The RNA-bound Dbp5 undergoes ATP hydrolysis and is activated by Gle1 in the presence of IP6. The formation of a ternary complex involving Dbp5, Gle1, and the nucleoporin Nup159 promotes ADP secretion and prevents RNA recombination. To date, several complex structures of Gle1 with its binding partners have been described; however, the structure of unbound Gle1 remains elusive. To investigate the structural features associated with complex formation, the crystal structure of N-terminally truncated Gle1 from Debaryomyces hansenii (DhGle1ΔN) was determined at a resolution of 1.5 Å. The DhGle1ΔN protein comprises 13 α-helices. Structural comparisons with homologs, all of which have been characterized in various complexes, revealed no significant conformational changes. However, several distinct secondary structural elements were identified in α1, α3, α4, and α8. This study may provide valuable insights into the architecture of yeast Gle1 proteins and their interactions with Dbp5, which is crucial for understanding the regulation of mRNA export.