Table 1.

Summary of E. coli tRNAs that contribute to +1 frameshifting at quadruplet codons

tRNA	Anticodon 5’-3’	ASL	Nucleotide 37 in the native-state	Occurrence in an elongation cycle and the kobs and yield (%) of +1 frameshifting
ProM	U*GG	Canonical	m1G37	Primarily in the stalled P site [64]
				Slow kobs at 4.8 × 10−3 s−1 [64]
				38% in the G37-state [64]
				N.D. in the m1G37-state and in the native-state [64]
ProL	GGG	Canonical	m1G37	Primarily in the stalled P site [64]
				Slow kobs at 2 × 10−3 s−1 [64]
				26% in the G37-state [64]
				8.1% in the native-state ([64]
				N.D. in the native-state + EF-P [64]
SufB2	GGG-G	Expanded	m1G37	Primarily during translocation [60]
				Fast kobs at 0.089 s−1 [60]
				90% in the G37-state [60]
				30% in the native-state [60]

The U* in the U*GG anticodon stands for mcmo⁵U34 [30], where the cmo⁵ moiety is the core that enables base pairing with all four natural nucleotides [31].

N.D: Not detectable