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. 2009 Jul;25(7):701–705. doi: 10.1089/aid.2009.0014

Table 2.

HIV gp41 Amino Acid Polymorphisms in the HR2 Regiona

AA# HXB2 ENF Resb Amino acid polymorphisms in test samplesc
100 N   1K
101 A   78T, 12N, 6D, 5V, 4S, 1K, 1I, 1G, 1X=A/D/I/N/T/Y
102 S   4T, 1N
103 W    
103–4 —   1SK
104 S    
104–5 —   3N, 3K, 1SKG, 1H
105 N   2S, 1X=N/K/R/S
106 K   24R, 1N
106–7 —   1TN, 1SLKD
107 S   10N, 22T, 1A, 1D, 1X=S/A/D/Y
108 L   18Y, 10V, 9Q, 9M, 5H, 5F, 2I, 1E, 1W
109 E   84D, 34N, 14S, 7K, 4H, 2G, 2T, 1R, 1A, 1X=N/S; 1X=D/I/N/V
110 Q   42E, 35D, 24K, 19Y, 8T, 5N, 5M, 3S, 4A, 2F, 2R, 1H, 1I, 1V, 1X=D/E/Y
111 I   1V
112 W    
112–3 —   1E
113 N   62D, 19G, 16E, 6Q, 5K, 4H, 2N, 1S
114 H   170N, 2H, 2K, 1S
115 T   168M, 4L, 1K, 1X=H/I/K
116 T    
117 W    
118 M   4R, 2I, 1L
119 E   85Q, 7D, 2K, 1A
120 W    
121 D   158E
122 R   72K
123 E    
124 I   1V
125 N   126D, 12S, 10E, 1A, 1H
126 N N126K 1D
127 Y   1H
128 T    
129 S   58G, 31D, 19N, 11E, 3R, 2Q, 2H, 1I, 1T, 1K, 1A, 4X=E/G; D/E/G; S/D/G/N; D/E/K/N
130 L   25I, 12T, 9V, 7E, 3S, 2F, 2Y, 1K, 1Q, 1X=I/P/T
131 I   1V
132 H   174Y
133 S   79T, 44N, 7K, 4D, 4R, 1Q, 1F, 1L, 1X=N/T
134 L    
135 I   56L
136 E   4T, 3G, 1Q, 1A, 1I, 1L, 1V
137 E E137K 27K, 15Q, 9N, 9D, 4G, 3A, 3T, 2I
138 S S138A 15A
139 Q    
140 N   4T, 11I, 3Y, 2H, 1S, 1D, 1F, 1R
a

The table shows the single letter code for the amino acid at each position (AA#) in the HXB2 reference strain (HXB2).

b

Mutations and amino acid polymorphisms that have been associated with enfuvirtide (ENF) resistance are shown (ENF Res).

c

Amino acids identified in the test samples that differ from the HXB2 sequence are shown using the single letter code. The number of test samples with each amino acid difference is shown (e.g., at position 126 in the HR2 region, one sample has the N126D substitution). Many of the amino acid substitutions were present as a mixture with the amino acid present in the HXB2 sequence (not shown). X indicates the presence of a degenerate nucleotide codon that encodes two or more amino acids in addition to the amino acid presence in the HXB2 sequence; in this case, the amino acids encoded at that position are shown (e.g., in one sample, the amino acids N = asparagine, K = lysine, R = arginine, and S = serine are encoded at position 105). Rows 126, 137, and 138 indicate the positions of accessory mutations that may increase the fitness of viruses with ENF resistance mutations. ENF resistance mutations were detected in some samples (bold).