Key elements in maintenance of the tRNA L-shape.
Based on in vivo selection of effective suppressor tRNAs from two different combinatorial gene libraries in which several nucleotides in the D and T-loops were randomized, we show that the position of the reverse-Hoogsteen base-pair in the T-loop, normally formed between nucleotides 54-58, co-varies with the length of the D-domain. When the D-domain has the normal length, the position of the reverse-Hoogsteen base-pair in the T-loop is always such that it allocates two unpaired nucleotides 59-60 for the bulge that fills the space between the D and T-domains. However, when the D-domain becomes shorter, the position of the reverse-Hoogsteen base-pair changes in the way that more nucleotides are now allocated to the T-loop bulge, so that the total length of the D-domain and of the bulge remains the same. Such compensation guarantees that in all tRNAs, the D and T-domains are always juxtaposed in the standard way. It also demonstrates the major role of the two T-loop elements, the bulge and the reverse-Hoogsteen base-pair, in the formation of the canonical tRNA L-shape.
Zagryadskaya
Ekaterina I
EI
Université de Montréal, Département de Biochimie, C.P. 6128, succursale Centre-Ville, Montréal, PQ, Canada H3C 3J7.
Kotlova
Natalia
N
Steinberg
Sergey V
SV
D001483:Base Sequence; D003198:Computer Simulation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012343:RNA, Transfer / Q000737:chemistry*
D012343:RNA, Transfer