For the Alt-R® CRISPR-Cpf1 crRNA, the input sequence can vary between 20 and 24 nucleotides. However, based on internal studies, we recommend using a 21-nucleotide sequence as input into the CRISPR-Cpf1 crRNA ordering tool (accessible at www.idtdna.com/CRISPR-Cpf1).
The ordering tool will automatically convert the DNA sequence to RNA during the ordering process. The 20-base constant region (loop domain) and modifications that confer intracellular nuclease resistance will be automatically added. The final Alt-R CRISPR-Cpf1 crRNA will be 40–44 bases.