Structure analysis
Multiple protein structure alignment
Compare three or more protein structures in one shared correspondence, then review conserved cores, outliers, and alignment consistency.
What is multiple protein structure alignment?
Multiple protein structure alignment is the process of placing three or more protein structures into a shared residue correspondence and coordinate frame. The result identifies conserved structural cores, insertions, flexible regions, and fold-level relationships that can remain visible after sequence similarity becomes weak.
Progressive methods such as FoldMason build an alignment from pairwise structural relationships, while other methods optimize a consensus or extend a reference-centered superposition. Structure selection, chains, domains, and conformation strongly affect the result.
ProteinIQ does not run a core multiple-structure alignment engine. Its review workflow accepts externally aligned coordinates, then uses FoldSeek clustering and pyRMSD to expose grouping and pairwise consistency without claiming to generate the original correspondence.
When to use multiple protein structure alignment
- A protein family has several structures. Use it for conserved-core analysis and structural classification.
- A curated set can be supplied. Start from three or more comparable structures and external alignment output.
- Global and local variation matter. Examine flexible domains and coverage alongside a consensus.
Benefits of multiple protein structure alignment
- Conserved geometry is visible. Shared cores can be located across a family.
- Comparison extends beyond sequence identity. Related structures can be studied with geometric evidence.
- Outliers and subfamilies emerge. Pairwise matrices help reveal nonuniform similarity.
Primary limitations
- Correspondence may not be unique. Different algorithms can produce different shared mappings.
- Flexible domains distort rigid consensus. One frame can hide important variation.
- Input selection changes the apparent core. Chains, domains, and states must be curated.
Multiple-structure alignment methods and applications
Reference-centered methods align every member to one chosen structure; progressive methods merge pairwise relationships; consensus optimization seeks a mapping shared across the set. Record whether scores describe pairs, columns, or the whole alignment, and retain residue mappings rather than just a mean RMSD.
Applications include conserved-core discovery, family classification, motif mapping, structure-guided sequence alignment, phylogenetic analysis, and comparison of experiments with predicted models. Domain-wise or state-specific analysis may be preferable when proteins have mobile domains or different assemblies.
How to run multiple protein structure alignment online
- Curate structures. Choose comparable chains, assemblies, domains, and conformational states.
- Run alignment externally. Use a dedicated multiple-structure method and retain its settings, scores, and coordinates.
- Inspect correspondence. Review cores, gaps, movements, flexible regions, and low coverage.
- Review consistency. Compare FoldSeek clusters with the pyRMSD pairwise matrix.
- Export provenance. Keep original alignment, reviewed coordinates, matrices, exclusions, and masks.
How to interpret multiple protein structure alignment results
Read RMSD with aligned residue count and coverage. Inspect outliers before removing them: they may be poor models or chains, but can also represent genuine conformational or evolutionary variation.
How multiple protein structure alignment works
The multiple alignment remains external; ProteinIQ reviews the aligned coordinates, clustering, and pairwise RMSD evidence.
- Curate structures. Choose comparable chains, assemblies, domains, and conformational states, recording experimental or prediction provenance.
- Run external alignment. Run a dedicated multiple-structure method such as FoldMason and retain its version, parameters, scores, and aligned coordinates.
- Inspect correspondence. Inspect conserved cores, gaps, domain movements, flexible regions, and structures with unusually low coverage.
- Review consistency. Load the aligned set into ProteinIQ to compare FoldSeek clustering with the pyRMSD pairwise matrix.
- Export provenance. Export the original alignment, reviewed coordinates, matrices, exclusions, and any downstream masks or consensus annotations.
Inputs and outputs
Check formats before running, then inspect and download the result from every workflow step.
Inputs
Structure-analysis inputs
PDBmmCIFFASTATSVThree or more curated protein structures plus aligned coordinates from a dedicated multiple-structure method.
Outputs
Reviewable results
PDBCSVTSVJSONFILESMultiple-structure correspondence, aligned coordinates, method-native confidence, FoldSeek clusters, and a pyRMSD matrix.
Tools for multiple protein structure alignment
Use these methods to prepare inputs, run the core analysis, inspect outputs, and validate the evidence described in this workflow.
pyRMSD
Calculate a pairwise RMSD matrix for a set of matching protein conformations
FoldSeek
Search structure databases or compare and cluster uploaded protein structures
USAlign
Align two protein structures and return TM-scores, RMSD, residue correspondence, and superposed coordinates
RMSD calculator
Superpose comparison structures on one reference and report RMSD values
DSSP
Assign secondary structure and solvent accessibility from protein coordinates
MolProbity
Check model geometry and steric quality before interpreting structural matches
PDB to FASTA converter
Extract protein sequences from coordinate files for sequence-aware review
MAFFT
Create a sequence alignment for comparison with structure-derived correspondence
Clustal Omega
Generate a protein multiple-sequence alignment for independent family context
MUSCLE5
Generate conventional or ensemble protein multiple-sequence alignments
SASA calculator
Calculate solvent-accessible surface area for matched structures
Radius of gyration
Compare global structural compactness across candidate models
Other structure analysis workflows
Compare related approaches based on the molecular system, available evidence, required inputs, and decision you need to support.
Frequently asked questions
Three or more curated protein structures plus aligned coordinates from a dedicated multiple-structure method.
Multiple-structure correspondence, aligned coordinates, method-native confidence, FoldSeek clusters, and a pyRMSD matrix.
Confirm accession, model, chain, biological assembly, domain boundaries, residue numbering, missing regions, alternate conformations, and prediction confidence. Repair coordinates only when necessary and retain both the original file and every preparation decision.
Use method-native scores together rather than selecting one universal number. TM-score emphasizes length-normalized global fold similarity, RMSD reports geometric deviation over the aligned atoms, and coverage shows how much of each structure actually corresponds.
No. Similar folds can support different functions, and local similarity can occur without shared global architecture. Review residue-level correspondence, domains, ligands, oligomeric state, taxonomy, sequence evidence, curated annotations, and experiments.
A complete multiple protein structure alignment project is generally quote-based. Current providers describe fold recognition and protein-structure analysis as customized services covering data review, method selection, modeling or comparison, validation, and interpretation rather than publishing one universal project price.
The cost depends on structure or sequence count, database scope, model preparation, method comparison, manual inspection, figures, annotation, and whether experimental follow-up is included. Open-source FoldSeek, US-align, and FoldMason can remove a software-license fee, but they do not remove expert analysis or compute requirements.
ProteinIQ self-service starts at $29 per month for academic Plus and $99 per month for commercial Pro, with the configured multiple protein structure alignment workflow estimated in credits before submission. Done-for-you analysis is scoped separately.
Start with a workflow you can inspect and edit
Add your inputs, review the settings, and keep every structure, score, table, and file connected to the step that produced it.