A newly identified class of highly thiostrepton-resistant mutants of the archaeon Halobacterium halobium carry a missense mutation at codon 18 within the gene encoding ribosomal protein L11. In the mutant proteins, a proline, conserved in archaea and bacteria, is converted to either serine or threonine. The mutations do not impair either the assembly of the mutant L11 into 70 S ribosomes in viv...

The L11 ribosomal protein operon of Escherichia coli contains the genes for L11 and L1 and is feedback regulated by the translational repressor L1. The mRNA target site for this repression is located close to the Shine-Dalgarno sequence for the first cistron, rp1K (L11). By use of a random mutagenesis procedure we have isolated and characterized a series of point mutations in the L11 leader mRN...

The ribosomal protein L11 in bacteria is posttranslationally trimethylated at multiple amino acid positions by the L11 methyltransferase PrmA, the product of the prmA gene. The role of L11 methylation in ribosome function or assembly has yet to be determined, although the deletion of Escherichia coli prmA has no apparent phenotype. We have constructed a mutant of the extreme thermophile Thermus...

Several studies have shown that ribosomal proteins (RPs) are important mediators of p53 activation in response to nucleolar disruption; however, the pathways that control this signalling function of RPs are currently unknown. We have recently shown that RPs are targets for the ubiquitin-like molecule NEDD8, and that NEDDylation protects RPs from destabilization. Here, we identify NEDD8 as a cru...

Ribosomal protein L11 is one of only two ribosomal proteins significantly iodinated when Escherichia coli 50 S subunits are modified by immobilized lactoperoxidase, and the major target has been shown previously to be tyrosine at position 7 in the N-terminal domain. This modification reduces in vitro termination activity with release factor (RF)-1 by 70-90%, but RF-2 activity is less affected (...

A high-expression system of L11 was constructed and its interaction with other elements of the ribosome were investigated using physicochemical methods. The gene rplK, coding for the protein L11 from the E. coli 50S ribosomal subunit was amplifyied, cloned and over-expressed. The protein L11 was purified under native and denaturing conditions, refolded and the structures of both proteins were c...

The L11 ribosomal protein operon of Escherichia coli contains the genes for L11 and L1 and is feedback regulated by the translational repressor L1. Both the L1 binding site on 23S rRNA and the L1 repressor target site on L11 operon mRNA share similar proposed secondary structures and contain some primary sequence identity. Several site-directed mutations in the binding region of 23S rRNA were c...

Impairment of ribosomal biogenesis can activate the p53 protein independently of DNA damage. The ability of ribosomal proteins L5, L11, L23, L26, or S7 to bind Mdm2 and inhibit its ubiquitin ligase activity has been suggested as a critical step in p53 activation under these conditions. Here, we report that L5 and L11 are particularly important for this response. Whereas several other newly synt...

Ribosome is responsible for protein synthesis in all organisms and ribosomal proteins (RPs) play important roles in the formation of a functional ribosome. L11 was recently shown to regulate p53 activity through a direct binding with MDM2 and abrogating the MDM2-induced p53 degradation in response to ribosomal stress. However, the studies were performed in cell lines and the significance of thi...