Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0016632 (Fox)
 1,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structures of 5S ribosomal RNAs from Escherichia coli and Bacillus stearothermophilus were examined by using ribonucleases A, T1, and T2 and a double helix specific cobra venom ribonuclease. By using both 5' and 3'-32P-end labeling methods and selecting for digested but intact 5S RNA molecules, we were able to distinguish between primary and secondary cutting positions and also to establish the relative degree of cutting. The data reveal the predicted similarities of the higher order structure in the two RNAs but also demonstrate a few significant differences. The data also provide direct evidence for three of the helical regions of the Fox and Woese model of 5S RNA [Fox, G. E., & Woese, C. (1975) Nature (London) 256, 505] and support other important structural features which include a nucleotide looped out from a helical region which has been proposed as a recognition site for protein L18.
 ...
PMID:Secondary structure of prokaryotic 5S ribosomal ribonucleic acids: a study with ribonucleases. 627 97

The binding of ribosomal protein L18 affects specific nucleotides in Escherichia coli 5S RNA as detected by dimethyl sulfate alkylation and RNase A digestion of the 5S-L18 complex. Most of the affected nucleotides are clustered and localize a site of RNA-protein interaction in and around the defined central helix [Fox, G. E. & Woese, C. (1975) Nature (London) 256, 505-507] of 5S RNA. Chemical carbethoxylation of the native 5S RNA with diethyl pyrocarbonate shows that a striking feature of this region is an unstacked adenosine residue at position 66. We propose that this residue exists as a singly bulged nucleotide extending the Fox and Woese central helix by two base pairs in the E. coli sequence (to positions 16-23/60-68) as well as in each of 61 (prokaryotic and eukaryotic) aligned 5S RNA sequences. In each case, the single bulged nucleotide is at the relative position of adenosine-66 in the RNA sequences. The presence of this putative bulged nucleotide appears to have been conserved in 5S RNA sequences throughout evolution, and its identity varies with major phylogenetic divisions. This residue is likely involved in specific 5S RNA-protein recognition or interaction in prokaryotic and eukaryotic ribosomes. The uridine-65 to adenosine-66 internucleotide bond is protected from RNase A digestion in the complex, and carbethoxylation of E. coli adenosine-66 prior to L18 binding affects formation of a stable RNA-protein complex. Thus, we identify a region of E. coli 5S RNA protected by the ribosomal protein L18 and propose that it contains a bulged nucleotide residue important in stable formation of this RNA-protein complex. This bulged residue appears to be evolutionarily conserved and phylogenetically defined in 5S RNA sequences in general, and consideration of other known RNA-protein binding sites shows that such a "bulged helix" may be a common feature of RNA-protein contact sites.
 ...
PMID:A "bulged" double helix in a RNA-protein contact site. 703 76