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Primary citation | PMID 30357364 |
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The Protein Data Bank (PDB) [1] is a database for the three-dimensional structural data of large biological molecules such as proteins and nucleic acids, which is overseen by the Worldwide Protein Data Bank (wwPDB). These structural data are obtained and deposited by biologists and biochemists worldwide through the use of experimental methodologies such as X-ray crystallography, NMR spectroscopy, and, increasingly, cryo-electron microscopy. All submitted data are reviewed by expert biocurators and, once approved, are made freely available on the Internet under the CC0 Public Domain Dedication. [2] Global access to the data is provided by the websites of the wwPDB member organisations (PDBe, [3] PDBj, [4] RCSB PDB, [5] and BMRB [6] ).
The PDB is a key in areas of structural biology, such as structural genomics. Most major scientific journals and some funding agencies now require scientists to submit their structure data to the PDB. Many other databases use protein structures deposited in the PDB. For example, SCOP and CATH classify protein structures, while PDBsum provides a graphic overview of PDB entries using information from other sources, such as Gene Ontology. [7] [8]
Two forces converged to initiate the PDB: a small but growing collection of sets of protein structure data determined by X-ray diffraction; and the newly available (1968) molecular graphics display, the Brookhaven RAster Display (BRAD), to visualize these protein structures in 3-D. In 1969, with the sponsorship of Walter Hamilton at the Brookhaven National Laboratory, Edgar Meyer (Texas A&M University) began to write software to store atomic coordinate files in a common format to make them available for geometric and graphical evaluation. By 1971, one of Meyer's programs, SEARCH, enabled researchers to remotely access information from the database to study protein structures offline. [9] SEARCH was instrumental in enabling networking, thus marking the functional beginning of the PDB.
The Protein Data Bank was announced in October 1971 in Nature New Biology [10] as a joint venture between Cambridge Crystallographic Data Centre, UK and Brookhaven National Laboratory, US.
Upon Hamilton's death in 1973, Tom Koetzle took over direction of the PDB for the subsequent 20 years. In January 1994, Joel Sussman of Israel's Weizmann Institute of Science was appointed head of the PDB. In October 1998, [11] the PDB was transferred to the Research Collaboratory for Structural Bioinformatics (RCSB); [12] the transfer was completed in June 1999. The new director was Helen M. Berman of Rutgers University (one of the managing institutions of the RCSB, the other being the San Diego Supercomputer Center at UC San Diego). [13] In 2003, with the formation of the wwPDB, the PDB became an international organization. The founding members are PDBe (Europe), [3] RCSB (US), and PDBj (Japan). [4] The BMRB [6] joined in 2006. Each of the four members of wwPDB can act as deposition, data processing and distribution centers for PDB data. The data processing refers to the fact that wwPDB staff review and annotate each submitted entry. [14] The data are then automatically checked for plausibility (the source code [15] for this validation software has been made available to the public at no charge).
The PDB database is updated weekly (UTC+0 Wednesday), along with its holdings list. [17] As of 10 January 2023 [update] , the PDB comprised:
Experimental Method | Proteins only | Proteins with oligosaccharides | Protein/Nucleic Acid complexes | Nucleic Acids only | Other | Oligosaccharides only | Total |
---|---|---|---|---|---|---|---|
X-ray diffraction | 152277 | 8969 | 8027 | 2566 | 163 | 11 | 172013 |
NMR | 12104 | 32 | 281 | 1433 | 31 | 6 | 13887 |
Electron microscopy | 9226 | 1633 | 2898 | 77 | 8 | 0 | 13842 |
Hybrid | 189 | 7 | 6 | 12 | 0 | 1 | 215 |
Neutron | 72 | 1 | 0 | 2 | 0 | 0 | 75 |
Other | 32 | 0 | 0 | 1 | 0 | 4 | 309 |
Total: | 173900 | 10642 | 11212 | 4091 | 202 | 22 | 200069 |
Most structures are determined by X-ray diffraction, but about 7% of structures are determined by protein NMR. When using X-ray diffraction, approximations of the coordinates of the atoms of the protein are obtained, whereas using NMR, the distance between pairs of atoms of the protein is estimated. The final conformation of the protein is obtained from NMR by solving a distance geometry problem. After 2013, a growing number of proteins are determined by cryo-electron microscopy.
For PDB structures determined by X-ray diffraction that have a structure factor file, their electron density map may be viewed. The data of such structures may be viewed on the three PDB websites.
Historically, the number of structures in the PDB has grown at an approximately exponential rate, with 100 registered structures in 1982, 1,000 structures in 1993, 10,000 in 1999, 100,000 in 2014, and 200,000 in January 2023. [18] [19]
The file format initially used by the PDB was called the PDB file format. The original format was restricted by the width of computer punch cards to 80 characters per line. Around 1996, the "macromolecular Crystallographic Information file" format, mmCIF, which is an extension of the CIF format was phased in. mmCIF became the standard format for the PDB archive in 2014. [20] In 2019, the wwPDB announced that depositions for crystallographic methods would only be accepted in mmCIF format. [21]
An XML version of PDB, called PDBML, was described in 2005. [22] The structure files can be downloaded in any of these three formats, though an increasing number of structures do not fit the legacy PDB format. Individual files are easily downloaded into graphics packages from Internet URLs:
http://www.pdb.org/pdb/files/4hhb.pdb.gz
or http://pdbe.org/download/4hhb
http://www.pdb.org/pdb/files/4hhb.xml.gz
or http://pdbe.org/pdbml/4hhb
The "4hhb
" is the PDB identifier. Each structure published in PDB receives a four-character alphanumeric identifier, its PDB ID. (This is not a unique identifier for biomolecules, because several structures for the same molecule—in different environments or conformations—may be contained in PDB with different PDB IDs.)
The structure files may be viewed using one of several free and open source computer programs, including Jmol, Pymol, VMD, Molstar and Rasmol. Other non-free, shareware programs include ICM-Browser, [23] MDL Chime, UCSF Chimera, Swiss-PDB Viewer, [24] StarBiochem [25] (a Java-based interactive molecular viewer with integrated search of protein databank), Sirius, and VisProt3DS [26] (a tool for Protein Visualization in 3D stereoscopic view in anaglyph and other modes), and Discovery Studio. The RCSB PDB website contains an extensive list of both free and commercial molecule visualization programs and web browser plugins.
Structural bioinformatics is the branch of bioinformatics that is related to the analysis and prediction of the three-dimensional structure of biological macromolecules such as proteins, RNA, and DNA. It deals with generalizations about macromolecular 3D structures such as comparisons of overall folds and local motifs, principles of molecular folding, evolution, binding interactions, and structure/function relationships, working both from experimentally solved structures and from computational models. The term structural has the same meaning as in structural biology, and structural bioinformatics can be seen as a part of computational structural biology. The main objective of structural bioinformatics is the creation of new methods of analysing and manipulating biological macromolecular data in order to solve problems in biology and generate new knowledge.
BioJava is an open-source software project dedicated to provide Java tools to process biological data. BioJava is a set of library functions written in the programming language Java for manipulating sequences, protein structures, file parsers, Common Object Request Broker Architecture (CORBA) interoperability, Distributed Annotation System (DAS), access to AceDB, dynamic programming, and simple statistical routines. BioJava supports a range of data, starting from DNA and protein sequences to the level of 3D protein structures. The BioJava libraries are useful for automating many daily and mundane bioinformatics tasks such as to parsing a Protein Data Bank (PDB) file, interacting with Jmol and many more. This application programming interface (API) provides various file parsers, data models and algorithms to facilitate working with the standard data formats and enables rapid application development and analysis.
A chemical file format is a type of data file which is used specifically for depicting molecular data. One of the most widely used is the chemical table file format, which is similar to Structure Data Format (SDF) files. They are text files that represent multiple chemical structure records and associated data fields. The XYZ file format is a simple format that usually gives the number of atoms in the first line, a comment on the second, followed by a number of lines with atomic symbols and cartesian coordinates. The Protein Data Bank Format is commonly used for proteins but is also used for other types of molecules. There are many other types which are detailed below. Various software systems are available to convert from one format to another.
The European Bioinformatics Institute (EMBL-EBI) is an intergovernmental organization (IGO) which, as part of the European Molecular Biology Laboratory (EMBL) family, focuses on research and services in bioinformatics. It is located on the Wellcome Genome Campus in Hinxton near Cambridge, and employs over 600 full-time equivalent (FTE) staff. Institute leaders such as Rolf Apweiler, Alex Bateman, Ewan Birney, and Guy Cochrane, an adviser on the National Genomics Data Center Scientific Advisory Board, serve as part of the international research network of the BIG Data Center at the Beijing Institute of Genomics.
The Protein Data Bank (PDB) file format is a textual file format describing the three-dimensional structures of molecules held in the Protein Data Bank, now succeeded by the mmCIF format. The PDB format accordingly provides for description and annotation of protein and nucleic acid structures including atomic coordinates, secondary structure assignments, as well as atomic connectivity. In addition experimental metadata are stored. The PDB format is the legacy file format for the Protein Data Bank which has kept data on biological macromolecules in the newer PDBx/mmCIF file format since 2014.
Crystallographic Information File (CIF) is a standard text file format for representing crystallographic information, promulgated by the International Union of Crystallography (IUCr). CIF was developed by the IUCr Working Party on Crystallographic Information in an effort sponsored by the IUCr Commission on Crystallographic Data and the IUCr Commission on Journals. The file format was initially published by Hall, Allen, and Brown and has since been revised, most recently versions 1.1 and 2.0. Full specifications for the format are available at the IUCr website. Many computer programs for molecular viewing are compatible with this format, including Jmol.
The Worldwide Protein Data Bank, wwPDB, is an organization that maintains the archive of macromolecular structure. Its mission is to maintain a single Protein Data Bank Archive of macromolecular structural data that is freely and publicly available to the global community.
The EM Data Bank or Electron Microscopy Data Bank (EMDB) collects 3D EM maps and associated experimental data determined using electron microscopy of biological specimens. It was established in 2002 at the MSD/PDBe group of the European Bioinformatics Institute (EBI), where the European site of the EMDataBank.org consortium is located. As of 2015, the resource contained over 2,600 entries with a mean resolution of 15Å.
The Cambridge Structural Database (CSD) is both a repository and a validated and curated resource for the three-dimensional structural data of molecules generally containing at least carbon and hydrogen, comprising a wide range of organic, metal-organic and organometallic molecules. The specific entries are complementary to the other crystallographic databases such as the Protein Data Bank (PDB), Inorganic Crystal Structure Database and International Centre for Diffraction Data. The data, typically obtained by X-ray crystallography and less frequently by electron diffraction or neutron diffraction, and submitted by crystallographers and chemists from around the world, are freely accessible on the Internet via the CSD's parent organization's website. The CSD is overseen by the not-for-profit incorporated company called the Cambridge Crystallographic Data Centre, CCDC.
Helen Miriam Berman is a Board of Governors Professor of Chemistry and Chemical Biology at Rutgers University and a former director of the RCSB Protein Data Bank. A structural biologist, her work includes structural analysis of protein-nucleic acid complexes, and the role of water in molecular interactions. She is also the founder and director of the Nucleic Acid Database, and led the Protein Structure Initiative Structural Genomics Knowledgebase.
In biology, a protein structure database is a database that is modeled around the various experimentally determined protein structures. The aim of most protein structure databases is to organize and annotate the protein structures, providing the biological community access to the experimental data in a useful way. Data included in protein structure databases often includes three-dimensional coordinates as well as experimental information, such as unit cell dimensions and angles for x-ray crystallography determined structures. Though most instances, in this case either proteins or a specific structure determinations of a protein, also contain sequence information and some databases even provide means for performing sequence based queries, the primary attribute of a structure database is structural information, whereas sequence databases focus on sequence information, and contain no structural information for the majority of entries. Protein structure databases are critical for many efforts in computational biology such as structure based drug design, both in developing the computational methods used and in providing a large experimental dataset used by some methods to provide insights about the function of a protein.
A crystallographic database is a database specifically designed to store information about the structure of molecules and crystals. Crystals are solids having, in all three dimensions of space, a regularly repeating arrangement of atoms, ions, or molecules. They are characterized by symmetry, morphology, and directionally dependent physical properties. A crystal structure describes the arrangement of atoms, ions, or molecules in a crystal..
Molecular models of DNA structures are representations of the molecular geometry and topology of deoxyribonucleic acid (DNA) molecules using one of several means, with the aim of simplifying and presenting the essential, physical and chemical, properties of DNA molecular structures either in vivo or in vitro. These representations include closely packed spheres made of plastic, metal wires for skeletal models, graphic computations and animations by computers, artistic rendering. Computer molecular models also allow animations and molecular dynamics simulations that are very important for understanding how DNA functions in vivo.
PDBsum is a database that provides an overview of the contents of each 3D macromolecular structure deposited in the Protein Data Bank (PDB).
The Protein Common Interface Database (ProtCID) is a database of similar protein-protein interfaces in crystal structures of homologous proteins.
The Re-referenced Protein Chemical shift Database (RefDB) is an NMR spectroscopy database of carefully corrected or re-referenced chemical shifts, derived from the BioMagResBank (BMRB). The database was assembled by using a structure-based chemical shift calculation program to calculate expected protein (1)H, (13)C and (15)N chemical shifts from X-ray or NMR coordinate data of previously assigned proteins reported in the BMRB. The comparison is automatically performed by a program called SHIFTCOR. The RefDB database currently provides reference-corrected chemical shift data on more than 2000 assigned peptides and proteins. Data from the database indicates that nearly 25% of BMRB entries with (13)C protein assignments and 27% of BMRB entries with (15)N protein assignments require significant chemical shift reference readjustments. Additionally, nearly 40% of protein entries deposited in the BioMagResBank appear to have at least one assignment error. Users may download, search or browse the database through a number of methods available through the RefDB website. RefDB provides a standard chemical shift resource for biomolecular NMR spectroscopists, wishing to derive or compute chemical shift trends in peptides and proteins.
Macromolecular structure validation is the process of evaluating reliability for 3-dimensional atomic models of large biological molecules such as proteins and nucleic acids. These models, which provide 3D coordinates for each atom in the molecule, come from structural biology experiments such as x-ray crystallography or nuclear magnetic resonance (NMR). The validation has three aspects: 1) checking on the validity of the thousands to millions of measurements in the experiment; 2) checking how consistent the atomic model is with those experimental data; and 3) checking consistency of the model with known physical and chemical properties.
In molecular biology, MobiDB is a curated biological database designed to offer a centralized resource for annotations of intrinsic protein disorder. Protein disorder is a structural feature characterizing a large number of proteins with prominent members known as intrinsically unstructured proteins. The database features three levels of annotation: manually curated, indirect and predicted. By combining different data sources of protein disorder into a consensus annotation, MobiDB aims at giving the best possible picture of the "disorder landscape" of a given protein of interest.
The Biological Magnetic Resonance Data Bank is an open access repository of nuclear magnetic resonance (NMR) spectroscopic data from peptides, proteins, nucleic acids and other biologically relevant molecules. The database is operated by the University of Wisconsin–Madison and is supported by the National Library of Medicine. The BMRB is part of the Research Collaboratory for Structural Bioinformatics and, since 2006, it is a partner in the Worldwide Protein Data Bank (wwPDB). The repository accepts NMR spectral data from laboratories around the world and, once the data is validated, it is available online at the BMRB website. The database has also an ftp site, where data can be downloaded in the bulk. The BMRB has two mirror sites, one at the Protein Database Japan (PDBj) at Osaka University and one at the Magnetic Resonance Research Center (CERM) at the University of Florence in Italy. The site at Japan accepts and processes data depositions.
The Macromolecular Crystallographic Information File (mmCIF) also known as PDBx/mmCIF is a standard text file format for representing macromolecular structure data, developed by the International Union of Crystallography (IUCr) and the Protein Data Bank It is an extension of the Crystallographic Information File (CIF), specifically for macromolecular data, such as proteins and nucleic acids, incorporating elements from the PDB file format.