Insert a monomer(s) to a DNA/RNA sequence from the DNA/RNA tab of the HELM Editor in Signals

Prior to this task: 

✔ HELM Editor must be opened.

✔ At least one HELM Monomer library must be available.

1️⃣ HELM Editor ➡ select DNA/RNA
2️⃣ DNA/RNA tab ➡ select //  [Ribose/Base/Phosphate] ➡ select corresponding settings [“HELM Monomer library name”] [“monomer symbol”]
3️⃣ ChemDraw doc canvas ➡ select left/right bond
4️⃣ DNA/RNA tab ➡ select [“monomer symbol”]

Supporting Knowledge

Notes:

• To generate a complementary strand for a single DNA/RNA strand, from the ChemDraw Document, navigate to HELM, select [More], then select [Generate complementary strand].
• To auto-pair two DNA/RNA strands with maximum complementarity, from the ChemDraw Document, navigate to HELM, select [More], then select [Auto-pair].
  • RNA and DNA strands are supported, including those with additional Chem or peptide monomers—hydrogen bonds are placed between complementary strands.
  • Hairpins can be generated from a single oligonucleotide sequence, including those with pendant chemical linkers or peptides—the region of maximum complementarity is identified, hydrogen bonds are placed between complementary nucleobases, and a hairpin loop is formed from the remaining unpaired nucleobases.
  • When one or more hydrogen bonds have been placed between nucleobases, the tool preserves them, finds the best remaining base complementarity, and adds the hydrogen bonds needed to complete the complementary strand or hairpin.
  • Partial selections of oligonucleotide strands are supported—compatible nucleobases within the selected regions are paired and the corresponding hydrogen bonds are added.
• To show 3’ and 5’ labels for DNA/RNA sequences, from the ChemDraw Document, select the [Open panel] icon in the upper right. From the Properties tab, under Biopolymer – Labels, select the Show 3’ and 5’ checkbox.
• To draw individual RNA/DNA monomers, select "None" from the secondary monomer dropdown, or use alt/option + monomer selection to add only the primary monomer (ribose, base, or phosphate) to the canvas.
• To draw biopolymers with multiple complementary RNA strands for a single sense strand, ChemDraw automatically detects the sense strand, identifies each complementary strand, and places each complement beneath the sense strand according to hydrogen bond positions, minimizing overlap for proper side-by-side alignment.