National Center for
3BNT: Crystal Structure Of The Homo Sapiens Mitochondrial Ribosomal Decoding Site In The Presence Of [co(nh3)6]cl3 (a1555g Mutant, Br-derivative)
The bacterial and mitochondrial ribosomal A-site molecular switches possess different conformational substates
Nucleic Acids Res. (2008) 36 p.2654-2666
The A site of the small ribosomal subunit participates in the fidelity of decoding by switching between two states, a resting 'off' state and an active decoding 'on' state. Eight crystal structures of RNA duplexes containing two minimal decoding A sites of the Homo sapiens mitochondrial wild-type, the A1555G mutant or bacteria have been solved. The resting 'off' state of the mitochondrial wild-type A site is surprisingly different from that of the bacterial A site. The mitochondrial A1555G mutant has two types of the 'off' states; one is similar to the mitochondrial wild-type 'off' state and the other is similar to the bacterial 'off' state. Our present results indicate that the dynamics of the A site in bacteria and mitochondria are different, a property probably related to the small number of tRNAs used for decoding in mitochondria. Based on these structures, we propose a hypothesis for the molecular mechanism of non-syndromic hearing loss due to the mitochondrial A1555G mutation.