Poster abstracts

Poster number 44 submitted by Neocles Leontis

Folding Complex RNA with Fewer Gs: Comparison of Composition and Distribution of Nucleotides in ribosomal RNA from Avian and Mammalian mitochondria.

Cailyn Davish (Chemistry Department Bowling Green State University), Maryam Hosseini (Chemistry Department Bowling Green State University), Neocles Leontis (Chemistry Department Bowling Green State University)

Abstract:
Mitochondrial ribosomes are derived from those of bacteria, and their SSU and LSU rRNAs show large-scale loss of peripheral elements, increase of ribosomal protein content, and drastic reduction of guanine nucleotides. Guanine is the base most sensitive to oxidative damage. In recent work (1), we showed that the remaining Gs in mmt rRNA are strategically concentrated at solvent inaccessible positions where they stabilize the rRNA structure by forming guanine-specific, RNA–RNA and RNA–protein interactions. Moreover, solvent-exposed guanines, conserved in bacteria, are replaced in mmt rRNA by bases less sensitive to oxidation. Birds and mammals shared a common ancestor over 200 million years ago, rather recently in relation to the origin of eukaryotes, but long ago for divergence in mitochondrial sequences to occur. They share warm-bloodedness and high metabolic rates, characteristics correlated with increased production of reactive oxygen species (ROS) in the mitochondrial matrix, where they can damage mitochondrial DNA and RNA (2,3). Here, we examine whether Avian mitochondrial (amt) rRNA shows the same adaptations to minimize or avoid oxidative damage. We compare the distribution of the conserved Gs in bacterial, mmt and amt SSU rRNA.

References:
References:
(1) Maryam Hosseini, Poorna Roy, Marie Sissler, Craig L Zirbel, Eric Westhof, Neocles Leontis; How to fold and protect mitochondrial ribosomal RNA with fewer guanines, Nucleic Acids Research, gky762, https://doi.org/10.1093/nar/gky762.
(2) López-Torres, M., & Barja, G. (2008). Mitochondrial Free Radical Production and Caloric Restriction: Implications in Vertebrate Longevity and Aging. Oxidative Stress in Aging, 149-162. doi:10.1007/978-1-59745-420-9_9
(3) Willi, J., Küpfer, P., Evéquoz, D., Fernandez, G., Katz, A., Leumann, C., & Polacek, N. (2018). Oxidative stress damages rRNA inside the ribosome and differentially affects the catalytic center. Nucleic Acids Research, 46(4), 1945-1957. doi:10.1093/nar/gkx1308.

Keywords: ribosomal RNA, mitochondrial, Guanine