Acidic, glycine-rich intrinsically disordered protein
A novel 376-residue intrinsically disordered protein: 100% predicted disorder, net charge −54.0 at pH 7.4 and no aromatic residues, built from a glycine-rich N-terminal block, a hydropathy-positive central region, an acidic basin and a polar C-terminal region. A converged 510 ns CALVADOS 2 ensemble shows an expanded chain (Rg 6.69 nm, ν 0.598) with no persistent intramolecular contacts, ranked a net-charge-dominated polyelectrolyte (low confidence; a self-avoiding-walk random coil is a close second). No detectable homology in nr, and no flagged structural neighbour in PDB, AlphaFold DB or ESM metagenomic databases.
evo_c1002M is a novel 376-residue intrinsically disordered protein (IDP) with a strongly acidic character (63 aspartates and glutamates against 9 basic residues). It is built from a glycine-rich N-terminal block, a hydropathy-positive central region, an acidic basin and a polar C-terminal region, uses 13 of the 20 amino acids and has no aromatic residues, no cysteines and no folded domain. Sequence analysis predicts 100% disorder. A converged CALVADOS 2 simulation shows an expanded, fast-exchanging chain in solution: one free-energy basin, no evidence of discrete states and no persistent intramolecular contacts. The only enriched contacts are 3 transient motifs, all within the glycine-rich N-terminal block. Throughout this dossier, REF marks the single atomistic reference conformation that seeds the simulation, ENS marks results from the simulated ensemble, and SEQ marks results computed from the sequence alone.
Strongly charged, expanded disordered chains are polymer-like building blocks whose behaviour is set largely by electrostatics, and this candidate is characterized at both ends. Its net charge is −54.0 at pH 7.4 (pI 3.28), carried mainly by one acidic basin, and the isolated chain has predictable dimensions (Rg 6.69 nm, Rh 4.57 nm) that a partner can check by SAXS or DLS; its ensemble Rg matches the self-avoiding-walk reference for this chain length. Independent evidence layers (sequence, disorder, ESMFold, reference conformation and ensemble contact maps) agree on a modular layout of distinct regions, and the two aggregation predictors disagree, which makes aggregation an explicit first experiment. It has no detectable homolog in nr, no flagged structural neighbour in PDB, AlphaFold DB or ESM metagenomic databases, and no RGD or IKVAV motif, and each use case below comes with a decisive first experiment.
Family F0001 — structure-only sequence/structure relationship. Closest partner evo_c1006M — TM-score 0.974, RMSD 1.17 Å, 376 aligned residues. 6 candidates fall below the same-fold threshold (TM 0.107–0.463).
Note: whole-chain TM-align is less meaningful for disordered chains (flagged in source report) — read this as sequence-and-shape-class kinship, not a folded-protein identity match.
Full composition, motif coordinates, and simulation trajectories are released to evaluating partners on request.
