Comparative study on tertiary contacts and folding of RNase P RNAs from a psychrophilic, a mesophilic/radiation-resistant, and a thermophilic bacterium.
RNA
; 27(10): 1204-1219, 2021 10.
Article
em En
| MEDLINE
| ID: mdl-34266994
In most bacterial type A RNase P RNAs (P RNAs), two major loop-helix tertiary contacts (L8-P4 and L18-P8) help to orient the two independently folding S- and C-domains for concerted recognition of precursor tRNA substrates. Here, we analyze the effects of mutations in these tertiary contacts in P RNAs from three different species: (i) the psychrophilic bacterium Pseudoalteromonas translucida (Ptr), (ii) the mesophilic radiation-resistant bacterium Deinococcus radiodurans (Dra), and (iii) the thermophilic bacterium Thermus thermophilus (Tth). We show by UV melting experiments that simultaneous disruption of these two interdomain contacts has a stabilizing effect on all three P RNAs. This can be inferred from reduced RNA unfolding at lower temperatures and a more concerted unfolding at higher temperatures. Thus, when the two domains tightly interact via the tertiary contacts, one domain facilitates structural transitions in the other. P RNA mutants with disrupted interdomain contacts showed severe kinetic defects that were most pronounced upon simultaneous disruption of the L8-P4 and L18-P8 contacts. At 37°C, the mildest effects were observed for the thermostable Tth RNA. A third interdomain contact, L9-P1, makes only a minor contribution to P RNA tertiary folding. Furthermore, D. radiodurans RNase P RNA forms an additional pseudoknot structure between the P9 and P12 of its S-domain. This interaction was found to be particularly crucial for RNase P holoenzyme activity at near-physiological Mg2+ concentrations (2 mM). We further analyzed an exceptionally stable folding trap of the G,C-rich Tth P RNA.
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Bases de dados:
MEDLINE
Assunto principal:
RNA Bacteriano
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RNA de Transferência
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Thermus thermophilus
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Pseudoalteromonas
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Deinococcus
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Ribonuclease P
Idioma:
En
Revista:
RNA
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Alemanha