Table 4. Number of AUG triplets and secondary-structure free energy for NAT1 5′-UTR sequences.

		uAUG*
Variant	Length	Strong	Adequate	Weak	Free energy (kcal/mol)†
Type IIA	166			1	−47.2
Type IIB	284		2	2	−80.5
Type IID	550	1		4	−167.7
Type IIE	700	2	2	6	−215.6

* The context of the uAUG was defined according to Meijer and Thomas [30] as ‘strong’ if it contained both an A, or G, at −3 and a G at +4, ‘adequate’ if it contained either of these nucleotides, and ‘weak’ if it contained neither.

† Calculated by the method of Mathews et al. [31] using the RNAstructure software. 1 kcal=4.184 kJ.