Abstract of the PDB Structure's related Publication:
In Escherichia coli, the pseudouridine synthase RsuA catalyzes formation of pseudouridine (psi) at position 516 in 16S rRNA during assembly of the 30S ribosomal subunit. We have determined the crystal structure of RsuA bound to uracil at 2.0 A resolution and to uridine 5'-monophosphate (UMP) at 2.65 A resolution. RsuA consists of an N-terminal domain connected by an extended linker to the central and C-terminal domains. Uracil and UMP bind in a cleft between the central and C-terminal domains near the catalytic residue Asp 102. The N-terminal domain shows structural similarity to the ribosomal protein S4. Despite only 15% amino acid identity, the other two domains are structurally similar to those of the tRNA-specific psi-synthase TruA, including the position of the catalytic Asp. Our results suggest that all four families of pseudouridine synthases share the same fold of their catalytic domain(s) and uracil-binding site.
RsuA catalyzes formation of pseudouridine at position 516 in hairpin 18 of 16S rRNA during assembly of the 30S ribosomal subunit. RsuA does not react with free unmodified 16S RNA, and only poorly with 30S particles containing unmodified RNA. The preferred substrate is an RNA fragment from residues 1 to 678 which has been complexed with 30S ribosomal proteins, suggesting that Y516 formation in vivo occurs at an intermediate stage of 30S assembly. RsuA consists of an N-terminal domain connected by an extended linker to the central and C-terminal domains. The N-terminal domain shows structural similarity to the ribosomal protein S4. RsuA is very similar in both catalytic domain structure and active site arrangement to the pseudouridine synthases RluD, TruB, and TruA, including the position of a catalytic Asp.
16S ribosomal RNA pseudouridine synthase RsuA of Escherichia coli: deletion, mutation of the conserved Asp102 residue, and sequence comparison among all other pseudouridine synthases.