<p>(<b>A</b>) Class 1a NESs carrying mutations at two hydrophobic positions and three spacer positions between Φ2 and Φ4. (<b>B</b>) Class 1c NESs carrying mutations at three positions within the spacer region between Φ2 and Φ3. These NES mutants were assayed for their nuclear export activity in NIH3T3 cells, and the activities were classified as scores from 1 to 10, as in <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003841#pcbi.1003841.s001" target="_blank">Figure S1</a>. The scores are indicated at the right columns of the corresponding sequences. Altered bases are highlighted in blue.</p
