Abstract of the PDB Structure's related Publication:
Pseudouridine synthases catalyze the isomerization of uridine to pseudouridine (Psi) in rRNA and tRNA. The pseudouridine synthase RluF from Escherichia coli (E.C. 4.2.1.70) modifies U2604 in 23S rRNA, and belongs to a large family of pseudouridine synthases present in all kingdoms of life. Here we report the domain architecture and crystal structure of the catalytic domain of E.coli RluF at 2.6A resolution. Limited proteolysis, mass spectrometry and N-terminal sequencing indicate that RluF has a distinct domain architecture, with the catalytic domain flanked at the N and C termini by additional domains connected to it by flexible linkers. The structure of the catalytic domain of RluF is similar to those of RsuA and TruB. RluF is a member of the RsuA sequence family of Psi-synthases, along with RluB and RluE. Structural comparison of RluF with its closest structural homologues, RsuA and TruB, suggests possible functional roles for the N-terminal and C-terminal domains of RluF.
RluF modifies U2604 in a stem-loop (helix 93 of the Peptidyl transferase Center on Domain V) of 23S RNA, while its homologue, RluB, modifies the adjacent base, U2605. Both uridines are in the same RNA stem, separated by only 4 A. The RNA stem-loop is bound to a conserved binding groove in the catalytic domain. A base from a bulge in the stem, A2602, folds into the stem, forcing one strand of the RNA stem to translate by one position and thus positioning U2604 to flip into the active site. The structure of the catalytic domain of RluF is similar to those of RsuA and TruB. RluF is a member of the RsuA family of pseudouridine synthases, along with RluB and RluE (but not TruB), present in all kingdoms of life.