Crystal structure of the human ATP-dependent splicing and export factor UAP56.
Pre-mRNA splicing requires the function of a number of RNA-dependent ATPases/helicases, yet no three-dimensional structure of any spliceosomal ATPases/helicases is known. The highly conserved DECD-box protein UAP56/Sub2 is an essential splicing factor that is also important for mRNA export. The expected ATPase/helicase activity appears to be essential for the UAP56/Sub2 functions. Here, we show that purified human UAP56 is an active RNA-dependent ATPase, and we also report the crystal structures of UAP56 alone and in complex with ADP, as well as a DECD to DEAD mutant. The structures reveal a unique spatial arrangement of the two conserved helicase domains, and ADP-binding induces significant conformational changes of key residues in the ATP-binding pocket. Our structural analyses suggest a specific protein-RNA displacement model of UAP56/Sub2. The detailed structural information provides important mechanistic insights into the splicing function of UAP56/Sub2. The structures also will be useful for the analysis of other spliceosomal DExD-box ATPases/helicases.
Shi
Hang
H
W. M. Keck Structural Biology Laboratory, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Cordin
Olivier
O
Minder
C Michael
CM
Linder
Patrick
P
Xu
Rui-Ming
RM
D000244:Adenosine Diphosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D053487:DEAD-box RNA Helicases; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D011487:Protein Conformation; D012313:RNA / Q000378:metabolism; D020365:RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D000244:Adenosine Diphosphate; D012313:RNA; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C487886:DDX39B protein, human; D053487:DEAD-box RNA Helicases; D020365:RNA Helicases