Three-dimensional Structure Databases

Cambridge Structural Database De Novo Ligand Design Pharmacophore and Drug Discovery Protein Data Bank (PDB) A Database of 3D Structural Information of Biological Macromolecules Structure Databases Three-dimensional Structure Generation Automation Three-dimensional Structure Searching. 

Figure 17.2 An example of prediction of the conformations of three CDR regions of a monoclonal antibody (top row) compared with the unrefined x-ray structure (bottom row). LI and L2 are CDR regions of the light chain, and HI is from the heavy chain. The amino acid sequences of the loop regions were modeled by comparison with the sequences of loop regions selected from a database of known antibody structures. The three-dimensional structure of two of the loop regions, LI and L2, were in good agreement with the preliminary x-ray structure, whereas HI was not. However, during later refinement of the x-ray structure errors were found in the conformations of HI, and in the refined x-ray structure this loop was found to agree with the predicted conformations. In fact, all six loop conformations were correctly predicted in this case. (From C. Chothia et al.. Science 233 755-758, 1986.)...

Greenidge, P.A., Carlsson, B., Biadh, L.G., and Gillner, M. Pharmacophores incorporating numerous excluded volumes defined by x-ray crystallographic structure in three-dimensional database searching application to the thyroid hormone receptor./. Med. Chem. 1998, 41, 2503-2512. 

There are two types of molecular structure database two-dimensional (2D) and three-dimensional. The 2D type stores atoms (chemical elements) and connectivity information (i.e., which atoms are bonded to which in a molecule). The 3D type stores, in addition, the x, y, z Cartesian co-ordinates of each atom in a molecule. 

The previous section shows how molecular structures stored in an RDBMS can be made available to client programs that traditionally read molecular structure files. The advantage of storing molecular structures in an RDBMS is that the information can be used from within the database, as well as by external clients. For example, it would be possible to search a table of molecular structures for three-dimensional overlap, much like it might be searched for substructure match. Of course, such search functions need to be written and installed as extensions to an RDBMS, just like the matches functions was done for substructure searches. This section shows some possible ways this might be accomplished. 

Stereochemistry Representation and Manipulation Structural Similarity Measures for Database Searching Structure and Substructure Searching Structure Databases Structure Representation Three-dimensional Structure Generation Automation Three-dimensional Structure Searching Topological Indices Topological Methods in Chemical Structure and Bonding. 

Bioinformatics is a relatively new discipline that is concerned with the collection, organisatic and analysis of biological data. It is beyond our scope to provide a comprehensive overvie of this discipline a few textbooks and reviews that serve this purpose are now available (s the suggestions for further reading). However, we will discuss some of the main rnethoc that are particularly useful when trying to predict the three-dimensional structure and fum tion of a protein. To help with this. Appendix 10.1 contains a limited selection of some of tf common abbreviations and acronyms used in bioinformatics and Appendix 10.2 lists sorr of the most widely used databases and other resources. 

A number of structured databases have been developed to classify proteins according to the three-dimensional structures. Many of these are accessible via the World Wide Web, T1 protein databanlc (PDB [Bernstein d al. 1977]) is the primary source of data about the stru tures of biological macromolecules and contains a large number of structures, but many i these are of identical proteins (complexed with different ligands or determined at differet resolutions) or are of close homologues. 

Good A C and J S Mason 1995. Three-Dimensional Structure Database Searches. In Lipkowitz K B and D B Boyd (Editors) Reviews in Computational Chemistry Volume 7. New York, VCH Publishers, pp. 67-117. 

Charifson P S, J J Corkery, M A Murcko and W P Walters 1999. Consensus Scoring A Method fc Obtaining Improved Hit Rates from Docking Databases of Three-Dimensional Structures int Proteins. Journal of Medicinal Chemistry 42 5100-5109. 

Homologous proteins have similar three-dimensional structures. They contain a core region, a scaffold of secondary structure elements, where the folds of the polypeptide chains are very similar. Loop regions that connect the building blocks of the scaffolds can vary considerably both in length and in structure. From a database of known immunoglobulin structures it has, nevertheless, been possible to predict successfully the conformation of hyper-variable loop regions of antibodies of known amino acid sequence. 

In this chapter, we will discuss the present status of CHIRBASE and describe the various ways in which two (2D) or three-dimensional (3D) chemical structure queries can be built and submitted to the searching system. In particular, the ability of this information system to locate and display neighboring compounds in which specified molecular fragments or partial structures are attached is one of the most important features because this is precisely the type of query that chemists are inclined to express and interpret the answers. Another aspect of the project has been concerned with the interdisciplinary use of CHIRBASE. We have attempted to produce a series of interactive tools that are designed to help the specialists or novices from different fields who have no particular expertise in chiral chromatography or in searching a chemical database. 

Martin YC, Bures MG, Willett P. Searching databases of three-dimensional structures. In Lipkowitz KB, Boyd DB, editors. Reviews in Computational Chemistry, Vol. 1. New York VCH, 1990. p. 213-63. 

This approach can be generalized to all possible types of experimental data that may be generated. All chemical structures available in public databases or internal to a company typically feature at least the in vitro binding assay data and additionally, the three-dimensional structure of the protein and/or bound ligand. A chemical compound C will therefore be ... 

Wang R, Fang X, Lu Y, Wang S. The PDBbind database collection of binding affinities for protein-ligand complexes with known three-dimensional structures. JMed Chem 2004 47 2977-80. 

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