High-resolution crystal structure of human Dim2/TXNL4B

TXNL4A (thioredoxin-like 4A) is an essential protein conserved from yeast to humans and is a component of the pre-mRNA splicing machinery. TXNL4B was identified as a TXNL4-family protein that also interacts with Prp6, an integral component of the U4/U6·U5 tri-snRNP complex, and has been shown to function in pre-mRNA splicing. A crystal structure of TXNL4B was determined at 1.33 Å resolution and refined to an R_work of 0.13 and an R_free of 0.18 with one native dimer in the asymmetric unit. Residues 1–33 of TXNL4B have previously been reported to be responsible for its interaction with Prp6. However, this region extends to the β-sheet core of the thioredoxin-fold structure of TXNL4B. This suggests that the interpretation of the previously reported GST pull-down results without considering the structure and stability of TXNL4B is debatable.