l:1911(1911) - Y
l:1917(1917) - Y
l:1915(1915) - Y
RluD makes pseudouridines at positions 1911, 1915, and 1917 in the loop of hairpin 69 in 23S RNA (Domain IV). These are the most conserved (and probably best studied) ribosomal pseudouridines known in Bacteria. RluD lacking cells exhibit growth defects and abnormal ribosome biogenesis. Moreover, the interactions around the Y1917 was shown to be critical for a proper interaction of helix 69 with release factors. When tested in vitro, recombinant RluD works best at low Mg concentrations. While in vivo, naturally occurring RluD modifies all three sites, U1911 has never been modified in vitro, even after conditions optimisation. RluD molecule consists of two subdomains, a catalytic subdomain and C-terminal subdomain with the RNA-binding cleft formed by loops extending from the catalytic subdomain. The catalytic subdomain of RluD has a similar fold as TruA, TruB and RsuA, with the location of the RNA-binding cleft, active-site and conserved, catalytic Asp residue 169 superposing in all four structures. The RluD N-terminal S4 domain is connected to the rest of the protein by a flexible linker. RluD is among the best studied RNA pseudouridine synthases.
A second function for pseudouridine synthases: A point mutant of RluD unable to form pseudouridines 1911, 1915, and 1917 in Escherichia coli 23S ribosomal RNA restores normal growth to an RluD-minus strain.
Gutgsell NS, Del Campo M, Raychaudhuri S, Ofengand J