TABLE 2.
Recovery of infectious virus after electroporation of NS2A charged-to-alanine scanning mutants
| Mutationa | Specific infectivityb | Titer atc: |
Compensating mutationd | ||
|---|---|---|---|---|---|
| 24 h | 48 h | 72 h | |||
| None (WT) | 5 × 105 | 1.3 × 107 | 1.2 × 108 | 8.0 × 107 | None |
| R22A-K23A-R24A | <3.3 × 101 | <5 | 9.3 × 103 | 1.7 × 104 | D343G (NS3) |
| AGG-AAA-AGA | <3.3 × 101 | ND | ND | ND | No virus recovered |
| GCG-GCA-GCA | <3.3 × 101 | ND | ND | ND | No virus recovered |
| D50A-K53A | <3.3 × 101 | <5 | <5 | <5 | No virus recovered |
| GAT-AAA | <3.3 × 101 | ND | ND | ND | No virus recovered |
| GCT-GCA | <3.3 × 101 | ND | ND | ND | No virus recovered |
| D70A | <3.3 × 101 | 1.2 × 103 | 4.0 × 106 | 4.1 × 107 | A70D (NS2A) |
| GAC | <3.3 × 101 | ND | ND | ND | A70D (NS2A) |
| GCC | <3.3 × 101 | ND | ND | ND | A70D (NS2A) |
| R99A-E100A-R101A | <3.3 × 101 | <5 | <5 | 7.5 × 102 | K124E (NS2A) |
| CGG-GAA-CGC | <3.3 × 101 | ND | ND | ND | K124E (NS2A) |
| GCG-GCA-GCC | <3.3 × 101 | ND | ND | ND | K124E (NS2A) |
| E162A-R164A | <3.3 × 101 | <5 | 1.8 × 102 | 1.3 × 104 | M168K (NS2A) |
| GAG-AGA | <3.3 × 101 | ND | ND | ND | M168K (NS2A) |
| GCG-GCA | <3.3 × 101 | ND | ND | ND | M168R (NS2A) |
a
Amino acids and numbers of residues with regard to the NS2A amino acid sequence mutagenized to alanine are indicated at the top. In the middle, the sequence of the wild type codon(s) is indicated. At the bottom, the codons after mutagenesis are shown, with the mutagenized nucleotide(s) underlined.
b
Determined by infectious center assay on BHK cells.
c
Determined by plaque assay on BHK cells. ND, not determined.
d
Each line represents the result of an independent experiment.