Marchler-Bauer, A. | bioRxiv Science

bioRxiv2021

iCn3D: from Web-based 3D Viewer to Structure Analysis Tool in Batch Mode

iCn3D was initially developed as a web-based 3D molecular viewer. It then evolved from visualization into a full-featured interactive structural analysis software. It became a collaborative research instrument through the sharing of permanent, shortened URLs that encapsulate not only annotated visual molecular scenes, but also all underlying data and analysis scripts in a FAIR manner. More recently, with the growth of structural databases, the need to analyze large structural datasets systematically led us to use Python scripts and convert the code to be used in Node.js scripts. We showed a few examples of Python scripts at https://github.com/ncbi/icn3d/tree/master/icn3dpython to export secondary structures or PNG images from iCn3D. Users just need to replace the URL in the Python scripts to export other annotations from iCn3D. Furthermore, any interactive iCn3D feature can be converted into a Node.js script to be run in batch mode, enabling an interactive analysis performed on one or a handful of protein complexes to be scaled up to analysis features of large ensembles of structures. Currently available Node.js analysis scripts examples are available at https://github.com/ncbi/icn3d/tree/master/icn3dnode. This development will enable ensemble analyses on growing structural databases such as AlphaFold or RoseTTAFold on one hand and Electron Microscopy on the other. In this paper, we also review new features such as DelPhi electrostatic potential, 3D view of mutations, alignment of multiple chains, assembly of multiple structures by realignment, dynamic symmetry calculation, 2D cartoons at different levels, interactive contact maps, and use of iCn3D in Jupyter Notebook as described at https://pypi.org/project/icn3dpy.

bioinformatics↗

bioRxiv2018

iCn3D, a Web-based 3D Viewer for the Visualization of Biomolecular Structure and Sequence Annotation

SummaryiCn3D (l-see-in-3D) is a web-based 3D molecular structure viewer implemented in JavaScript. It invites users to explore sequence-structure relationships by displaying 3D structures, protein and nucleotide sequences, and biological annotations such as protein domains, Single Nucleotide Variations, functional sites, molecular contacts, as well as user defined features. Customized and user-annotated displays can be shared with colleagues or publishers via a simple URL, or embedded in web pages as live 3D displays. iCn3D is unique in its ability to simultaneously show 3D structure, 2D molecular networks and interactions, and 1D protein and nucleotide sequences through an integrated sequence/annotation browser. Arbitrary molecular features can be selected in any of the 1D/2D/3D windows as sets of molecules or residues, utilizing flexible user interfaces. These selections are synchronized dynamically in all displays. They can, for example, be shown as tracks in the 1D sequence/annotation browser with simultaneous 3D representations. They can be saved and reused throughout a single user session, or exported for subsequent sessions and further external analysis. iCn3D is rich in structural analysis and visualization features and has a built-in user interface that supports both command line- and menu-driven operation. Session commands can be saved, replayed and shared. iCn3D can display superimposed structures obtained from NCBFs VAST+ structural alignment resource, for comparative analysis of tertiary or quaternary structure. iCn3D can also display electron density maps for crystal structures and export files for 3D printing. The following example URL exemplifies some of the 1D/2D/3D representations: https://www.ncbi.nlm.nih.gov/Structure/icn3d/full.html?mmdbid=1TUP&showanno=1&show2d=1&showsets=1.\n\nAvailability and implementationiCn3D is freely available to the public. Its source code is available at https://github.com/ncbi/icn3d.

bioinformatics↗