Crystal structure of the catalytic domain of human Pus1
Classification:
RNA BINDING PROTEIN
Technique:
X-Ray Diffraction
Resolution:
1.8
R value free:
0.227
R value observed:
0.188
R value work:
0.186
Abstract of the PDB Structure's related Publication:
Human pseudouridine (Ψ) synthase Pus1 (hPus1) modifies specific uridine residues in several non-coding RNAs: tRNA, U2 spliceosomal RNA, and steroid receptor activator RNA. We report three structures of the catalytic core domain of hPus1 from two crystal forms, at 1.8Å resolution. The structures are the first of a mammalian Ψ synthase from the set of five Ψ synthase families common to all kingdoms of life. hPus1 adopts a fold similar to bacterial Ψ synthases, with a central antiparallel β-sheet flanked by helices and loops. A flexible hinge at the base of the sheet allows the enzyme to open and close around an electropositive active-site cleft. In one crystal form, a molecule of Mes [2-(N-morpholino)ethane sulfonic acid] mimics the target uridine of an RNA substrate. A positively charged electrostatic surface extends from the active site towards the N-terminus of the catalytic domain, suggesting an extensive binding site specific for target RNAs. Two α-helices C-terminal to the core domain, but unique to hPus1, extend along the back and top of the central β-sheet and form the walls of the RNA binding surface. Docking of tRNA to hPus1 in a productive orientation requires only minor conformational changes to enzyme and tRNA. The docked tRNA is bound by the electropositive surface of the protein employing a completely different binding mode than that seen for the tRNA complex of the Escherichia coli homologue TruA.
Specificity of this enzyme was not studied in details. Most probably it is very similar to the specificity of its yest and mouse homologs.
Mitochondrial. Exist in two isoforms. Reduced or no activity of Pus1 is related to mitochondrial myopathy and sideroblastic anemia (MLASA).
Can modify the Steroid receptor RNA Activator (SRA).
A small RNA derived from RNA coactivator SRA blocks steroid receptor signaling via inhibition of Pus1p-mediated pseudouridylation of SRA: evidence of a novel RNA binding domain in the N-terminus of steroid receptors.
In Human Pseudouridine Synthase 1 (hPus1), a C-Terminal Helical Insert Blocks tRNA from Binding in the Same Orientation as in the Pus1 Bacterial Homologue TruA, Consistent with Their Different Target Selectivities.
Czudnochowski N, Wang AL, Finer-Moore J, Stroud RM
Mitochondrial myopathy and sideroblastic anemia (MLASA): missense mutation in the pseudouridine synthase 1 (PUS1) gene is associated with the loss of tRNA pseudouridylation.
Patton JR, Bykhovskaya Y, Mengesha E, Bertolotto C, Fischel-Ghodsian N
A small RNA derived from RNA coactivator SRA blocks steroid receptor signaling via inhibition of Pus1p-mediated pseudouridylation of SRA: evidence of a novel RNA binding domain in the N-terminus of steroid receptors.
In Human Pseudouridine Synthase 1 (hPus1), a C-Terminal Helical Insert Blocks tRNA from Binding in the Same Orientation as in the Pus1 Bacterial Homologue TruA, Consistent with Their Different Target Selectivities.
Mitochondrial myopathy and sideroblastic anemia (MLASA): missense mutation in the pseudouridine synthase 1 (PUS1) gene is associated with the loss of tRNA pseudouridylation.
Partial activity is seen with many substitutions of highly conserved active site residues in human Pseudouridine synthase 1.
Pseudouridine synthase 1: a site-specific synthase without strict sequence recognition requirements.
Steroid receptor RNA activator (SRA) modification by the human pseudouridine synthase 1 (hPus1p): RNA binding, activity, and atomic model.