# Peptide structure prediction Predict plausible peptide conformations while preserving cyclization, sequence length, flexibility, and model-specific structural assumptions. [Open this workflow](https://proteiniq.io/app/workflows/templates?template=peptide-structure-prediction)[Contact sales](https://proteiniq.io/contact) ## More protein structure prediction workflows ## Tools for peptide structure prediction Use these methods to prepare inputs, run the core analysis, inspect outputs, and validate the evidence described in this workflow. [![HighFold](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Falphafold-2.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### HighFold Predict cyclic peptide structures with cyclic constraints](https://proteiniq.io/app/highfold)[![ESMFold](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fesmfold.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### ESMFold Predict a sequence-derived peptide conformation](https://proteiniq.io/app/esmfold)[![Boltz-2](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fboltz-2.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### Boltz-2 Predict peptide or peptide-complex structures](https://proteiniq.io/app/boltz-2)[![Chai-1](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fchai-1.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### Chai-1 Model multi-component peptide systems](https://proteiniq.io/app/chai-1)[![OpenFold3](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fopenfold-3.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### OpenFold3 Generate an alternative all-atom prediction](https://proteiniq.io/app/openfold-3)[![PeptideBuilder](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fpeptidebuilder.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### PeptideBuilder Build a geometry-controlled coordinate baseline](https://proteiniq.io/app/peptidebuilder)[![PDBFixer](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fpdb-fixer-featured.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### PDBFixer Repair compatible peptide PDB files](https://proteiniq.io/app/pdb-fixer)[![MolProbity](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fmolprobity.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### MolProbity Review all-atom geometry](https://proteiniq.io/app/molprobity)[![Ramachandran plot](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Framachandran-plot.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### Ramachandran plot Inspect peptide backbone torsions](https://proteiniq.io/app/ramachandran-plot)[![SASA calculator](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fsasa-calculator.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### SASA calculator Calculate solvent exposure](https://proteiniq.io/app/sasa-calculator)[![Radius of gyration](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fradius-of-gyration.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### Radius of gyration Compare conformational compactness](https://proteiniq.io/app/radius-of-gyration)[![USAlign](https://proteiniq.io/_next/image?url=%2Fimages%2Ftools%2Fusalign.webp&w=96&q=75&dpl=dpl_J8tu6aF3F41kEvMFgYtuMXes1ynJ) ### USAlign Compare predicted conformations](https://proteiniq.io/app/usalign) ## What is peptide structure prediction? Peptide structure prediction is the computational process of estimating one or more three-dimensional conformations for a short amino-acid chain. Peptides often have shallow energy landscapes and may remain disordered or adopt different conformations in solution, membranes, and bound complexes. Peptides are not simply small globular proteins. Short chains can populate ensembles, and one predicted structure may represent only one plausible state. Cyclization and disulfides materially change the conformational problem. This workflow compares a cyclic-peptide-aware model with general structure predictors. Match the tool to the chemistry and preserve whether a returned conformation is unbound, constrained, or predicted in a complex. ### When to use peptide structure prediction Use peptide modeling when chemistry and conformational context are explicit: - A cyclic peptide needs a topology-aware model. - Several plausible conformers are needed for structural comparison. - A peptide model will guide NMR, circular dichroism or binding studies. ### Strengths and limitations A cyclic-aware predictor can represent connectivity that general protein predictors may miss. Comparing model families and keeping alternative conformations makes the topology assumption visible. Short peptides often occupy an ensemble rather than one stable fold. Terminal chemistry, disulfides and cyclization may be represented differently across tools, and a free peptide can change shape upon binding. Confidence in one model is not a population estimate. ## Peptide-model interpretation Cyclic prediction must represent non-linear connectivity or positional offsets. HighFold is designed for supported cyclic constraints, while general predictors provide comparisons but may not enforce the same chemistry. For flexible linear peptides, an ensemble or bound-state prediction can be more informative than one unbound model. Compare compactness, secondary structure, intramolecular contacts, and compatibility with NMR or circular-dichroism evidence. ## Applications of peptide structure prediction Peptide modeling can suggest conformations for a short chain when experimental coordinates are unavailable. The question should state whether the peptide is linear, cyclic or constrained by disulfides because those chemistries change the conformational space. Comparing a cyclic-aware model with general protein predictors can show how much the topology assumption matters. A low-energy or high-confidence isolated peptide conformation may differ from its receptor-bound state. ## How to run peptide structure prediction online 1. **Define topology.** Record sequence, terminal chemistry, head-to-tail cyclization and disulfide constraints where relevant. 2. **Run the cyclic-aware branch.** Use [HighFold](https://proteiniq.io/app/highfold) when the peptide chemistry fits its supported cyclic representation. 3. **Compare general predictors.** Generate a separate [ESMFold](https://proteiniq.io/app/esmfold) model from the same sequence. 4. **Review the third model.** Inspect [Boltz-2](https://proteiniq.io/app/boltz-2) coordinates and its native confidence without assuming the three tools model identical chemistry. 5. **Select structural hypotheses.** Check bond continuity, clashes and alternative conformations before planning binding or structural experiments. ## How to interpret peptide structure prediction results First verify that a model represents the intended cyclic or linear topology. Compare local confidence and geometry only after this check; a visually compact model with incorrect connectivity should be rejected. Peptides often populate ensembles in solution and can change shape on binding. One predicted structure supports a hypothesis, not a measured population, affinity or function. ## How peptide structure prediction works Run HighFold, ESMFold, and Boltz-2 from one peptide sequence and compare model-specific conformations. 1. **Define peptide chemistry.** Define the peptide sequence and record cyclization, disulfides, and noncanonical chemistry. 2. **Encode sequence and constraints.** Run [HighFold](https://proteiniq.io/app/highfold) when the supported cyclic constraints match the molecule. 3. **Run complementary models.** Run [ESMFold](https://proteiniq.io/app/esmfold) and Boltz-2 as complementary general-model branches. 4. **Compare conformations.** Compare backbone conformations, compactness, confidence, and constraint satisfaction. 5. **Validate the relevant state.** Export plausible alternatives and validate the biologically relevant state with experiment or complex context. ## Inputs and outputs Check formats before running, then inspect and download the result from every workflow step. ### Inputs #### Research input `FASTA``PDB``mmCIF` An amino-acid sequence with documented head-to-tail cyclization, disulfides, or other supported constraints. ### Outputs #### Prediction and review outputs `PDB``mmCIF``CSV``JSON` Predicted peptide structures, model-native confidence, and downloadable PDB or mmCIF files. ## Frequently asked questions AI answers from our docs. 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