How should circular amino acid sequences be represented in a patent application?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

According to MPEP 2412.05(d), circular amino acid sequences should be represented as follows:

• Choose an amino acid as residue position number 1
• Number continuously through the entire sequence in the amino to carboxy direction
• Do not represent amino and carboxy termini

The MPEP states, “When an amino acid sequence is circular in configuration and the ring consists solely of amino acid residues linked by peptide bonds, i.e., the sequence has no amino and carboxy termini, applicant must choose the amino acid in residue position number 1. Numbering is continuous through the entire sequence in the amino to carboxy direction.” This approach ensures a consistent representation of circular amino acid sequences in patent applications.