21037010
not annotated - annotated - LINNAEUS only
Inactivation of the RluD pseudouridine synthase has minimal effects on growth and ribosome function in wild-type Escherichia coli and Salmonella enterica.
The Escherichia coli rluD gene encodes a pseudouridine synthase responsible for the pseudouridine (Psi) modifications at positions 1911, 1915, and 1917 in helix 69 of 23S rRNA. It has been reported that deletion of rluD in K-12 strains of E. coli is associated with extremely slow growth, increased readthrough of stop codons, and defects in 50S ribosomal subunit assembly and 30S-50S subunit association. Suppressor mutations in the prfB and prfC genes encoding release factor 2 (RF2) and RF3 that restore the wild type-growth rate and also correct the ribosomal defects have now been isolated. These suppressors link helix 69 Psi residues with the termination phase of protein synthesis. However, further genetic analysis reported here also reveals that the slow growth and other defects associated with inactivation of rluD in E. coli K-12 strains are due to a defective RF2 protein, with a threonine at position 246, which is present in all K-12 strains. This is in contrast to the more typical alanine found at this position in most bacterial RF2s, including those of other E. coli strains. Inactivation of rluD in E. coli strains containing the prfB allele from E. coli B or in Salmonella enterica, both carrying an RF2 with Ala246, has negligible effects on growth, termination, or ribosome function. The results indicate that, in contrast to those in wild bacteria, termination functions in E. coli K-12 strains carrying a partially defective RF2 protein are especially susceptible to perturbation of ribosome-RF interactions, such as that caused by loss of h69 Psi modifications.
Ann file
T1 Species 113 129 Escherichia coli
N1 Reference T1 Taxonomy:562
T2 Species 134 153 Salmonella enterica
N2 Reference T2 Taxonomy:28901
T3 Species 161 177 Escherichia coli
N3 Reference T3 Taxonomy:562
T4 Species 396 403 E. coli
N4 Reference T4 Taxonomy:562
T5 Species 987 999 E. coli K-12
N5 Reference T5 Taxonomy:562
T6 Species 1102 1106 K-12
N6 Reference T6 Taxonomy:562
T7 Species 1236 1243 E. coli
N7 Reference T7 Taxonomy:562
T8 Species 1277 1284 E. coli
N8 Reference T8 Taxonomy:562
T9 Species 1325 1334 E. coli B
N9 Reference T9 Taxonomy:562
T10 Species 1341 1360 Salmonella enterica
N10 Reference T10 Taxonomy:28901
T11 Species 1556 1568 E. coli K-12
N11 Reference T11 Taxonomy:562
T12 Species 380 384 K-12
N12 Reference T12 Taxonomy:562