31residue

31residue is a length-based designation used in biochemistry and structural biology to refer to a polypeptide or protein fragment consisting of 31 amino acid residues. It is not a standardized protein name, but rather a descriptor applied to sequences, synthetic peptides, or fragments within larger proteins that contain 31 residues. The term is common in discussions of short peptides used in experimental assays or in computational modeling, where uniform length facilitates comparison across diverse sequences.

In experimental contexts, 31-residue peptides can be designed to test folding propensity, stability, membrane interaction, or antimicrobial activity. In silico studies, 31residue sequences serve as convenient benchmarks for conformational sampling, energy functions, and docking or docking-free modeling, due to their manageable size while still exhibiting nontrivial structural possibilities.

Characteristics of 31-residue peptides depend primarily on the amino acid composition and the environment. They can range from predominantly unstructured to highly helical or beta-like, and may form transient structures in aqueous solution or upon binding partners. Design considerations include solubility, propensity for aggregation, and the presence of motifs that influence folding or activity.

While there is no universal database entry for "31residue," many research articles report 31-residue peptides as model systems or controls. The term is used more as a practical label than a formal classification, and it often appears in datasets where sequence length is a key parameter.

See also: Peptide, Short peptide, Protein length, Amino acid residue.