Enter a text-based sequence to a polymer from the Text tab of the HELM Editor in Signals

Prior to this task:

✔ HELM Editor must be opened. 

1️⃣ HELM Editor ➡ select Text
2️⃣ Text tab ➡ select Enter text-based sequence data ➡ enter text [“sequence type name”] Generate complementary strand*
3️⃣ Text tab ➡ select [Insert]

Supporting Knowledge

*Complementary strand for a DNA/RNA sequence(s) with hydrogen bonding.

When entering a DNA/RNA sequence with its complementary strand, the user must select FASTA DNA or FASTA RNA as the sequence type. The template strand will be inserted in the 5’ to 3’ direction on the ChemDraw document canvas, with the complementary strand aligned underneath in the 3’ to 5’ direction.

These complementary DNA/RNA strands are created with hydrogen bonds automatically mapped between the strands. The hydrogen bonds follow Watson-Crick base pairing rules. To display the hydrogen bonds, from the ChemDraw document, navigate to Structure and select [More], then select [Expand label]. The pairing information is also included in the HELM string when the “Copy As FASTA” option is selected.

Notes:

• It is not possible to enter or paste multiple sequences simultaneously.
• When pasting a FASTA peptide sequence with header information into a Chemical Drawing, either directly or via the Text tab of the HELM Editor, the FASTA header will appear as an annotation.
• Atom-mapped SMILES are supported when inserting HELM strings. Additionally, when generating a HELM string for a sequence that includes an unknown or inline monomer, the resulting HELM string will automatically incorporate atom-mapped SMILES.
• When generating a HELM string for a sequence containing hydrogen bonds, the output includes pairing details.