Active suppressor tRNAs with a double helix between the D- and T-loops

Area of Science:

• Molecular Biology
• RNA Structure and Function

Background:

• The T54-A58 reverse-Hoogsteen base-pair is crucial for maintaining the L-shape conformation of transfer RNA (tRNA).
• This conserved base-pair is essential for the structural integrity and function of tRNA.

Purpose of the Study:

• To investigate the structural and functional consequences of the absence of the T54-A58 base-pair in tRNA.
• To identify alternative mechanisms that maintain tRNA conformation in the absence of T54-A58.

Main Methods:

• In vivo selection of active suppressor tRNA clones.
• Analysis of tRNA sequences to identify structural alterations.

Main Results:

• 51 active suppressor tRNA clones were selected, none containing the T54-A58 base-pair.
• 49 of these clones featured complementary regions in the D and T-loops, forming an inter-loop double helix.
• This inter-loop helix appears to functionally replace the T54-A58 base-pair in stabilizing tRNA structure.

Conclusions:

• The study reveals an alternative mechanism for maintaining tRNA L-shape conformation.
• An inter-loop double helix can act as a compensatory element for the absence of the T54-A58 base-pair.
• This highlights the adaptability of RNA molecules and the potential for synonymous structural arrangements in functional RNAs.