3qtm
From Proteopedia
Structure of S. pombe nuclear import adaptor Nro1 (Space group P21)
Structural highlights
Function[ETT1_SCHPO] Required for correct translation termination (By similarity). Positive regulator of the stability of the N-terminal transcription factor domain (Sre1N) of sre1 which is released from the membrane and enters the nucleus to activate hypoxic gene expression. Acts also as a direct inhibitor of ofd1. Functions probably by inhibiting the ability of the ofd1 to accelerate Sre1N degradation in absence of oxygen.[1] [2] Publication Abstract from PubMedIn Saccharomyces cerevisiae, the putative 2-OG-Fe(II) dioxygenase Tpa1 and its partner Ett1 have been shown to impact mRNA decay and translation. Hence, inactivation of these factors was shown to influence stop codon read-though. In addition, Tpa1 represses, by an unknown mechanism, genes regulated by Hap1, a transcription factor involved in the response to levels of heme and O(2). The Schizosaccharomyces pombe orthologs of Tpa1 and Ett1, Ofd1, and its partner Nro1, respectively, have been shown to regulate the stability of the Sre1 transcription factor in response to oxygen levels. To gain insight into the function of Nro1/Ett1, we have solved the crystal structure of the S. pombe Nro1 protein deleted of its 54 N-terminal residues. Nro1 unexpectedly adopts a Tetratrico Peptide Repeat (TPR) fold, a motif often responsible for protein or peptide binding. Two ligands, a sulfate ion and an unknown molecule, interact with a cluster of highly conserved amino acids on the protein surface. Mutation of these residues demonstrates that these ligand binding sites are essential for Ett1 function in S. cerevisiae, as investigated by assaying for efficient translation termination. Structural and functional analysis of Nro1/Ett1: a protein involved in translation termination in S. cerevisiae and in O2-mediated gene control in S. pombe.,Rispal D, Henri J, van Tilbeurgh H, Graille M, Seraphin B RNA. 2011 Jul;17(7):1213-24. Epub 2011 May 24. PMID:21610214[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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