Comparative study on tertiary contacts and folding of RNase P RNAs from a psychrophilic, a mesophilic/radiation-resistant, and a thermophilic bacterium

Abstract

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 Mg 2+ concentrations (2 mM). We further analyzed an exceptionally stable folding trap of the G,C-rich Tth P RNA.

Radiation-resistant bacteria in desiccated soil and their potentiality in applied sciences

“…As a result of rapid emerging resistance against the preexisting antibiotics, the search for new metabolites obtained from such extreme habitats is crucial to contain human and animal diseases ( Gabani and Singh, 2013 ; Nayak et al, 2021 ). Rr bacteria are not only resistant to oxidation and radiation but survive with fluctuation of temperature and are categorized into mesophile, thermophile, and hyperthermophile subgroups ( Ranawat and Rawat, 2017 ; Li et al, 2020 ; Marszalkowski et al, 2021 ). These bacteria are found in less non-arid habitats than in arid ones, as plenty of photochemical production of ROS in the desert ecosystem facilitates their origin, diversity, and abundance ( Rainey et al, 2005 ).…”