DichroPipeline: A suite of online and downloadable tools and resources for protein circular dichroism spectroscopic data analyses, interpretations, and their interoperability with other bioinformatics tools and resources.

Circular Dichroism (CD) spectroscopy is a widely-used method for characterizing individual protein structures in solutions, membranes, films and macromolecular complexes, as well as for probing macromolecular interactions, conformational changes associated with binding substrates, and in different functionally-related environments. This paper describes a series of related computational and display tools that have been developed over many years to aid in those characterizations and functional interpretations. The new DichroPipeline described herein links a series of format-compatible data processing, analysis, and display tools to enable users to facilely produce the spectra, which can then be made available in the Protein Circular Dichroism Data Bank (https://pcddb.

The PCDDB (Protein Circular Dichroism Data Bank): A Bioinformatics Resource for Protein Characterisations and Methods Development.

The Protein Circular Dichroism Data Bank (PCDDB) [https://pcddb.cryst.bbk.

Tools and methods for circular dichroism spectroscopy of proteins: a tutorial review.

Circular dichroism (CD) spectroscopy is a widely-used method in biochemistry, structural biology and pharmaceutical chemistry. More than 24 000 papers published in the past decade have included CD characterisations of proteins; many of those studies have also included other complementary chemical, biophysical, and computational chemistry methods. This tutorial review describes the background to the technique of CD spectroscopy and good practice methods for high quality data collection.

Identification of a druggable binding pocket in the spike protein reveals a key site for existing drugs potentially capable of combating Covid-19 infectivity.

Background: Following the recent outbreak of the new coronavirus pandemic (Covid-19), the rapid determination of the structure of the homo-trimeric spike glycoprotein has prompted the study reported here. The aims were to identify potential "druggable" binding pockets in the protein and, if located, to virtual screen pharmaceutical agents currently in use for predicted affinity to these pockets which might be useful to restrict, reduce, or inhibit the infectivity of the virion.

Results: Our analyses of this structure have revealed a key potentially druggable pocket where it might be viable to bind pharmaceutical agents to inhibit its ability to infect human cells.

PDBMD2CD: providing predicted protein circular dichroism spectra from multiple molecular dynamics-generated protein structures.

PDBMD2CD is a new web server capable of predicting circular dichroism (CD) spectra for multiple protein structures derived from molecular dynamics (MD) simulations, enabling predictions from thousands of protein atomic coordinate files (e.g. MD trajectories) and generating spectra for each of these structures provided by the user.

2StrucCompare: a webserver for visualizing small but noteworthy differences between protein tertiary structures through interrogation of the secondary structure content.

2StrucCompare is a webserver whose primary aim is to visualize subtle but functionally important differences between two related protein structures, either of the same protein or related homologues, with similar or functionally different tertiary structures. At the heart of the package is identifying and visualizing differences between conformations at the secondary structure and at the residue level, such as contact differences or side chain conformational differences found between two protein chains. The protein secondary structures are determined according to four established methods (DSSP, STRIDE, P-SEA and STICKS), and as each employs different assignment strategies, small conformational differences between the two structures can give rise to paired residues being denoted as having different secondary structure features with the different methods.

DichroMatch at the protein circular dichroism data bank (DM@PCDDB): A web-based tool for identifying protein nearest neighbors using circular dichroism spectroscopy.

Circular dichroism spectroscopy is a well-used, but simple method in structural biology for providing information on the secondary structure and folds of proteins. DichroMatch (DM@PCDDB) is an online tool that is newly available in the Protein Circular Dichroism Data Bank (PCDDB), which takes advantage of the wealth of spectral and metadata deposited therein, to enable identification of spectral nearest neighbors of a query protein based on four different methods of spectral matching. DM@PCDDB can potentially provide novel information about structural relationships between proteins and can be used in comparison studies of protein homologs and orthologs.

PDB2CD visualises dynamics within protein structures.

Proteins tend to have defined conformations, a key factor in enabling their function. Atomic resolution structures of proteins are predominantly obtained by either solution nuclear magnetic resonance (NMR) or crystal structure methods. However, when considering a protein whose structure has been determined by both these approaches, on many occasions, the resultant conformations are subtly different, as illustrated by the examples in this study.

PDB2CD: a web-based application for the generation of circular dichroism spectra from protein atomic coordinates.

Motivation: Circular dichroism (CD) spectroscopy is extensively utilized for determining the percentages of secondary structure content present in proteins. However, although a large contributor, secondary structure is not the only factor that influences the shape and magnitude of the CD spectrum produced. Other structural features can make contributions so an entire protein structural conformation can give rise to a CD spectrum.

PCDDB: new developments at the Protein Circular Dichroism Data Bank.

The Protein Circular Dichroism Data Bank (PCDDB) has been in operation for more than 5 years as a public repository for archiving circular dichroism spectroscopic data and associated bioinformatics and experimental metadata. Since its inception, many improvements and new developments have been made in data display, searching algorithms, data formats, data content, auxillary information, and validation techniques, as well as, of course, an increase in the number of holdings. It provides a site (http://pcddb.

ValiDichro: a website for validating and quality control of protein circular dichroism spectra.

Circular dichroism (CD) spectroscopy is widely used in structural biology as a technique for examining the structure, folding and conformational changes of proteins. A new server, ValiDichro, has been developed for checking the quality and validity of CD spectral data and metadata, both as an aid to data collection and processing and as a validation procedure for spectra to be included in publications. ValiDichro currently includes 25 tests for data completeness, consistency and quality.

Circular dichroism spectral data and metadata in the Protein Circular Dichroism Data Bank (PCDDB): a tutorial guide to accession and deposition.

The Protein Circular Dichroism Data Bank (PCDDB) is a web-based resource containing circular dichroism (CD) and synchrotron radiation circular dichroism spectral and associated metadata located at http://pcddb.cryst.bbk.

DichroMatch: a website for similarity searching of circular dichroism spectra.

Circular dichroism (CD) spectroscopy is a widely used method for examining the structure, folding and conformational changes of proteins. A new online CD analysis server (DichroMatch) has been developed for identifying proteins with similar spectral characteristics by detecting possible structurally and functionally related proteins and homologues. DichroMatch includes six different methods for determining the spectral nearest neighbours to a query protein spectrum and provides metrics of how similar these spectra are and, if corresponding crystal structures are available for the closest matched proteins, information on their secondary structures and fold classifications.

PCDDB: the Protein Circular Dichroism Data Bank, a repository for circular dichroism spectral and metadata.

The Protein Circular Dichroism Data Bank (PCDDB) is a public repository that archives and freely distributes circular dichroism (CD) and synchrotron radiation CD (SRCD) spectral data and their associated experimental metadata. All entries undergo validation and curation procedures to ensure completeness, consistency and quality of the data included. A web-based interface enables users to browse and query sample types, sample conditions, experimental parameters and provides spectra in both graphical display format and as downloadable text files.

The protein circular dichroism data bank, a Web-based site for access to circular dichroism spectroscopic data.

The Protein Circular Dichroism Data Bank (PCDDB) is a newly released resource for structural biology. It is a web-accessible (http://pcddb.cryst.

2Struc: the secondary structure server.

Summary: The defined secondary structure of proteins method is often considered the gold standard for assignment of secondary structure from three-dimensional coordinates. However, there are alternative methods. '2Struc: The Secondary Structure Server' has been created as a single point of access for eight different secondary structure assignment methods.

Synchrotron radiation circular dichroism (SRCD) spectroscopy: an enhanced method for examining protein conformations and protein interactions.

CD (circular dichroism) spectroscopy is a well-established technique in structural biology. SRCD (synchrotron radiation circular dichroism) spectroscopy extends the utility and applications of conventional CD spectroscopy (using laboratory-based instruments) because the high flux of a synchrotron enables collection of data at lower wavelengths (resulting in higher information content), detection of spectra with higher signal-to-noise levels and measurements in the presence of absorbing components (buffers, salts, lipids and detergents). SRCD spectroscopy can provide important static and dynamic structural information on proteins in solution, including secondary structures of intact proteins and their domains, protein stability, the differences between wild-type and mutant proteins, the identification of natively disordered regions in proteins, and the dynamic processes of protein folding and membrane insertion and the kinetics of enzyme reactions.

Light flux density threshold at which protein denaturation is induced by synchrotron radiation circular dichroism beamlines.

New high-flux synchrotron radiation circular dichroism (SRCD) beamlines are providing important information for structural biology, but can potentially cause denaturation of the protein samples under investigation. This effect has been studied at the new CD1 dedicated SRCD beamline at ISA in Denmark, where radiation-induced thermal damage effects were observed, depending not only on the radiation flux but also on the focal spot size of the light. Comparisons with similar studies at other SRCD facilities worldwide has lead to the estimation of a flux density threshold under which SRCD beamlines should be operated when samples are to be exposed to low-wavelength vacuum ultraviolet radiation for extended periods of time.

Combining sequence-based prediction methods and circular dichroism and infrared spectroscopic data to improve protein secondary structure determinations.

Background: A number of sequence-based methods exist for protein secondary structure prediction. Protein secondary structures can also be determined experimentally from circular dichroism, and infrared spectroscopic data using empirical analysis methods. It has been proposed that comparable accuracy can be obtained from sequence-based predictions as from these biophysical measurements.

Novel methods for secondary structure determination using low wavelength (VUV) circular dichroism spectroscopic data.

Background: Circular Dichroism (CD) spectroscopy is a widely used method for studying protein structures in solution. Modern synchrotron radiation CD (SRCD) instruments have considerably higher photon fluxes than do conventional lab-based CD instruments, and hence have the ability to routinely measure CD data to much lower wavelengths. Recently a new reference dataset of SRCD spectra of proteins of known structure, designed to cover secondary structure and fold space, has been produced which includes low wavelength (vacuum ultraviolet - VUV) data.

Protein Circular Dichroism Data Bank (PCDDB): data bank and website design.

The Protein Circular Dichroism Data Bank (PCDDB) is a new deposition data bank for validated circular dichroism spectra of biomacromolecules. Its aim is to be a resource for the structural biology and bioinformatics communities, providing open access and archiving facilities for circular dichroism and synchrotron radiation circular dichroism spectra. It is named in parallel with the Protein Data Bank (PDB), a long-existing valuable reference data bank for protein crystal and NMR structures.

Analysing the ability to retain sidechain hydrogen-bonds in mutant proteins.

Motivation: Hydrogen bonds are one of the most important inter-atomic interactions in biology. Previous experimental, theoretical and bioinformatics analyses have shown that the hydrogen bonding potential of amino acids is generally satisfied and that buried unsatisfied hydrogen-bond-capable residues are destabilizing. When studying mutant proteins, or introducing mutations to residues involved in hydrogen bonding, one needs to know whether a hydrogen bond can be maintained.

The Protein Circular Dichroism Data Bank (PCDDB): a bioinformatics and spectroscopic resource.

This article describes the development and creation of the Protein Circular Dichroism Data Bank (PCDDB), a deposition and searchable data bank for validated circular dichroism spectra located at http://pcddb.cryst.bbk.

Bioinformatics analyses of circular dichroism protein reference databases.

Motivation: Circular dichroism (CD) spectroscopy has become established as a key method for determining the secondary structure contents of proteins which has had a significant impact on molecular biology. Many excellent mathematical protocols have been developed for this purpose and their quality is above question. However, reference database sets of proteins, with CD spectra matched to secondary structure components derived from X-ray structures, provide the key resource for this task.

Overcoming protein denaturation caused by irradiation in a high-flux synchrotron radiation circular dichroism beamline.

It has been established that the new circular dichroism beamline CD12 has sufficiently high flux at low wavelengths to cause apparent irradiation problems with protein samples while their synchrotron radiation circular dichroism (SRCD) spectra are being collected. The cause of this effect has been extensively investigated and is reported in an accompanying paper [Wien et al. (2005).