ICM-Bio

ICM-Bio, developed by Molsoft L.L.C., is a comprehensive bioinformatics software package designed for researchers who need a powerful environment for sequence analysis, alignment, and database searching. It provides tools for manipulating sequences, alignments, profiles, and databases both interactively and in batch mode, with direct connectivity to 3D molecular models. ICM-Bio includes all the features found in ICM-Browser-Pro, making it a complete solution for structural bioinformatics workflows.

A key strength of ICM-Bio is its fully interactive alignment editor and annotator, which bridges the gap between sequence-level analysis and 3D structural visualization. Researchers can explore sequence conservation directly in three dimensions, making it particularly valuable for structural biology, homology modeling, and evolutionary analysis.

Alignment Algorithms and Accuracy

• Includes two high-quality global pairwise alignment algorithms with zero-end penalties (ZEGA), featuring double-affinity gap penalties and dual insertions.
• Empirical statistics derived for many residue substitution matrices and gap penalties to evaluate the probability that two aligned sequences share the same structural fold.
• Statistics can be applied locally to evaluate alignment reliability, identify alternative alignments, and detect repeats using probability-weighted dot-plots.
• ZEGA-based database searches for distant relatives and structural similarities, with the potential to identify more homologues than a standard BLAST search.
• Results are presented in a linked table format for easy navigation and review.

Alignment Editor and Annotation

• Easy-to-use editor for both pairwise and multiple alignments, designed to protect the integrity of alignments by preventing unintended changes.
• Supports shading, boxing, and annotating alignment regions.
• Allows font color changes, bold formatting, and addition of titles to alignments.
• Alignments can be exported as high-quality images or in a variety of standard alignment formats.
• Copy and paste selected regions of an alignment, and copy the full alignment to clipboard.

Multiple Sequence Alignment Capabilities

• Dynamic and feature-rich multiple sequence alignment editor with easy drag-and-drop alignment construction.
• Uses accurate pairwise sequence-sequence, sequence-profile, and profile-profile alignments to build multiple sequence alignments via a hierarchical, evolutionary tree-guided procedure.
• Neighbor-joining tree construction algorithm and weighted profile construction ensure high-quality alignments.
• Batch generation of multiple sequence alignments with full control over alignment parameters via the shell.
• Link alignments directly to 3D protein structures in the graphical display — selections made in the alignment are propagated onto the protein structure.
• Extract sub-alignments, cut vertical alignment blocks, reorder sequences, extract unique sequences, and hide or compress gaps.
• Display consensus sequences, sequence profiles, sequence rulers, sequence trees, and secondary structure annotations.
• Color alignments by a variety of built-in and user-defined color schemes, including hydrophobicity and adjustable consensus strength.
• Build residue number and residue label tables from alignments.
• Make complex selections in the alignment, particularly useful when linked to 3D structures.
• View differences within the alignment and display sequences in unaligned form.

Sequence Analysis Features

• Read sequences and alignments in many formats, including FASTA.
• Direct links to the UniProt sequence database and Pfam.
• Calculate sequence residue content with tabular and graphical display of residue frequencies.
• Predict sequence secondary structure and perform six-frame translation.
• Set sequence type (protein or DNA) and use the fully interactive sequence editor.
• Save sequences as images or in a variety of output formats.

Sequence Search and Database Tools

• Fast tool to search any BLAST-formatted database with a query sequence and generate an alignment on the fly.
• Search by sequence similarity and sequence homology.
• Pattern searches, PROSITE and profile searches, and tools for indexing and querying flat-file sequence databases.
• Annotation transfer functions and sequence-structure connectivity tools.

Sequence-Structure Alignment and Homology Modeling

• Interactive alignment editor for easy alignment and tether editing, with color-coded selections for easy identification.
• Evolutionary relationships displayed as neighbor-joining trees, 2D principal component distributions, and 3D distributions analyzable in stereo using molecular graphics controls.
• Sequence threading uses both secondary structure and template 3D structure for sequence-structure alignment.
• Search sequences interactively or in batch through any database to generate a list of possible homologues sorted and evaluated by probability of structural significance.
• Alignments generated can be directly used in homology modeling workflows.
• PostScript image export for publication-quality results.

ICM-Bio supports a wide range of alignment methods including ZEGA, H-align, Needleman-Wunsch, Smith-Waterman, and Wilbur-Lipman, with adjustable parameters such as gap open and gap extension penalties. Its tight integration between sequence analysis and 3D structural visualization makes it a versatile platform for structural bioinformatics, evolutionary studies, and homology-based modeling in both interactive and automated batch workflows.