For a translated feature, how can I ensure that a non-ATG start codon is translated as methionine?
Select the Feature

The following procedure can be performed when you first create a translated feature, but the lesson will assume that the translated feature already exists.
In this example, the feature is E. coli transaldolase B, which has a GTG start codon.
Click the translated feature to select it.
Open the Edit Feature Dialog

To open the Edit Feature dialog, click Features → Edit Feature... .
Alternatively, you can double-click the feature.
Open the Feature Translation Options Dialog

To open the Feature Translation Options dialog, click Options... .

Click the Translate the first codon as Methionine check box. The first amino acid will change to an "M", and will be shown in red.
View the Updated Feature

Close both dialogs by pressing OK. The start codon will now be translated as methionine.