Table 2.

Nucleotide and deduced amino acid sequence mutations identified in the 2C and 3D coding regions of parental and 3D-G64 mutant virus populations after 1 or 13 passages in RD cells in the presence of the mutagen ribavirin (400 μM)

Population	Nucleotide			Amino acid			BLOSUM62a (similarity score)
	Positionb	Amino acid sequence mutation at:		Position	Amino acid sequence mutation at:
		Passage 1	Passage 13		Passage 1	Passage 13
26M	4604	T	A	2C-175	M	K	−1
	4633 (2)	A	C	2C-185	K	R	2
	4634 (2)	A	G	2C-185	K	R	2
	4974	G	T	2C-298	K	N	0
	4995	G	A	2C-305	T	T	4
	6048 (2)	A	G	3D-36	G	G	6
	6130	G	C	3D-64	G	R	−2
	6500	T	C	3D-187	L	L	4
	6532	T	C	3D-198	F	L	0
	6730–6731	TC	CT	3D-264	S	L	−2
G64N	4638 (2)	T	C	2C-186	D	D	6
	4894	G	A	2C-272	E	K	1
	4896	G	A	2C-272	E	K	1
	4958	G	A	2C-293	R	K	2
	6048	A	G	3D-36	G	G	6
	6071	A	G	3D-44	H	R	0
	6074	G	C	3D-45	S	T	1
	6108	G	C	3D-56	Q	H	0
	6121–6122	AA	CC	3D-61	K	P	−1
	6172 (2)	G	C	3D-78	A	P	−1
	6429 (2)	C	A	3D-163	R	R	5
G64T	6448 (2)	G	A	3D-169	K	K	5
	6451	G	T	3D-170	K	N	0
G64R	6981	G	C	3D-347	T	T	4
S264L	6225	G	C	3D-95	M	I	1

^aBLOSUM62 is an amino acid substitution matrix for pairwise protein sequence alignments used to analyze the similarities between amino acid residues. BLOSUM62 matrices with high scores are associated with closely related residues. In contrast, low scores are associated with distantly related residues (39).

^bValues in this column in parentheses represent the number of repetitions for each mutation observed out of the total number of nucleotides sequenced.