Overview: Advanced Search
What is Advanced Search?
Besides the 3D coordinates of atoms in the structure, all PDB entries include a variety of meta-data about the experiment, polymer sequences, and ligands present in the structure. Information and annotations from other data resources are also connected to each PDB entry.
Why use Advanced Search?
RCSB PDB Advanced Search options allow you to query all data in the coordinate files and their associated annotations to rapidly find structures, polymers, and ligands relevant to the topic of interest.
Advanced Search Query Builder Interface
The Advanced Search Query Builder interface features powerful options for constructing complex searches and managing results. Attribute queries can be seamlessly combined with sequence and structure similarity searches.
Queries: Using the Advanced Search Options
The Advanced Search options allow you to construct complex composite queries to quickly find structures and/or information related to the topic of interest by
- defining the query either as specifically or as broadly as is appropriate for the search being performed.
- organizing search results in a manner that facilitates rapid identification of the matches of interest.
Criteria for Searching
RCSB PDB Advanced Search options allow you to query the archive in four distinct ways:
- Attribute Search: This option allows for three types of searches based on specific text-based or numerical properties of entries, assemblies, or ligands.
- Full Text searches of PDB entries and their associated annotations
- Structural Attributes searches of textual and numerical properties of PDB structure(s), their associated experimental details that relate to polymer molecules (e.g., name, identifiers)
- Chemical Attributes searches of the names and classifications of small molecules (ligands), inhibitors, drugs, etc. that are present in PDB structures
- Sequence Based Search: This option allows for searches based on the polymer sequences present in PDB structures.
- Sequence search uses the polymer sequences of all or a significant portion of the proteins and nucleic acids present in a structure.
- Sequence Motif search uses a short polymer query sequence.
- Structure Based Search: This option enables searches based on 3D structural alignments.
- Structure search is based on 3D shape.
- Structure Motif search is based on the local arrangement of a selected set of structural building blocks in a given PDB structure.
- Chemical Search: This option allows for searches based on chemical information (e.g., chemical formula and descriptors like SMILES, InChI).
Composite and complex Boolean queries can be constructed using the 'AND', 'OR', and 'NOT' options available on the Advanced Search interface. These operators can be applied to specific attributes or groups of attributes and used as follows:
- AND: identify structures, polymers, ligands, or assemblies that meet all the specified criteria.
- OR: identify structures, polymers, ligands, or assemblies that meet any one of the specified criteria.
- NOT: exclude structures, polymers, ligands, or assemblies that meet the specified criteria.
Different search types (i.e., attribute-based, sequence-based, structure-based, and chemical information-based searches) may be combined to construct complex composite queries. As you assemble a composite query, you have the option of running subqueries to assess how many structures, polymers, etc. match those selected portions of the overall query.
Search Result Return Options
PDB archive-wide searches can return two kinds of results:
- Structural data: PDB entry, entity, and/or assembly information pertaining to one or more structures in the archive.
- Molecular definitions: chemical component dictionary and BIRD molecule matches to specific search criteria.
Before you launch a search you can select the type of results you wish to see. For example, do you wish to find PDB structures or entries, polymer entities (e.g., that match a sequence), assembly of biological macromolecules, or small molecule ligands? These can be specified by selecting the appropriate Return Options presented as a pulldown menu in the lower left corner of the Advanced Search Query Builder.
Several options for the types of search results are available in the pulldown, with the default option being “Structures”.
- Structures - PDB entries, designated with a 4-character alphanumeric identifier, e.g. 1Q2W. See grouping options for Structures.
- Polymer Entities - distinct (chemically unique) polymeric molecules present in PDB entries, specifically proteins (polypeptides), DNA (polydeoxyribonucleotide), and RNA (polyribonucleotide). See grouping options for Structures.
- Non-polymer Entities - small chemicals (enzyme cofactors, ligands, ions, etc) defined as non-polymers in the coordinate file. A non-polymer Entity ID is a combination of a PDB ID and entity ID, e.g., 4HHB_3. This option can be useful when searching for small chemicals within their macromolecular context, for instance covalently bound ligands such as ATP in 2CCH (entity 2CCH_4).
- Assemblies - the macromolecular quaternary structure believed to be the functional form of the molecule (also referred to as the “biological unit”)
- Molecular Definitions - includes standard and modified amino acids (e.g., ALA) and nucleotides (e.g., A), small molecule ligands (e.g., ATP, or HEM) as they are defined in the wwPDB Chemical Component Dictionary (CCD), and peptide-like molecules as they are defined in the Biologically Interesting molecule Reference Dictionary (BIRD), (e.g., PRD_000010).
The Results Page
Depending on the Return options selected, the search results page displays lists of structures or PDB entries, polymer entities, ligands, assemblies etc.
- View - the search results can be viewed in a variety of formats:
- Summary - every search hit is displayed with an image and summary information.
- Gallery - every search hit is displayed with an image only.
- Compact - every search hit is displayed with summary information only.
Options for Grouping Results
Redundancy occurs at many levels (such as the level of sequence or structure similarity), and a variety of different grouping methods can be applied to PDB data in order to provide a non-redundant view. Available grouping options can be selected from the “grouped by” dropdown at the bottom of the Advanced Search Query Builder. Learn more about grouping search results here.