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Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> Dabs Single Domain Antibodies Daunorubicin
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2D-Page
A powerful technique to resolve thousands of proteins. In the first dimension, isoelectric focussing separates proteins based on isoelectric points in the tube gel and in the second dimension, SDS-PAGE resolves the proteins separated in the first dimension into peptides based on their size.
D-amino acid
Isomeric form of amino acid that is rare in natural peptides/proteins except in some bacterial cell walls.
D-banding
A technique for identifying regions of DNase I sensitivity, that corresponds to regions of open chromatin that are potentially transcriptionally active.
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Dalton (Da)
A unit of mass equivalent to the mass of a hydrogen atom (1.66 ´ 10-24g). It is named after the famous nineteenth century chemist, John Dalton (1766-1844). The molecular weight of compounds is expressed as kilodaltons (kDa) or megadaltons (MDa), equal to 1 ´ 106 daltons respectively.
Dam methylase
An enzyme that methylates the N6 position of all adenine residues within the 5 GATC sequences. It is involved in mismatch repair.
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Dansylation
A method used to add dansyl groups to free amino groups in proteins to determine the N-terminal sequences.
Dansyl chloride
A compound that reacts with the amino group of an amino acid to produce a fluorescent derivative that can be measured. This is used to identify the amino terminal peptides.
Dark reactions
Reactions that take place in the dark such as the dark reactions of photosynthesis.
Data Definition Language (DDL)
A database system that provides a data definition language to specify the database schema.
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Darwinian cloning
Selections of a clone from a large number of random starting points, instead of isolating a natural gene or designing an artificial one. Molecules which are more similar to those required are selected, mutated to generate new variants, and reselected. The cyclic continues until the required molecule is obtained. This system offers the advantage of selecting from a vast number of possibilities.
DAS (Distributed Annotation System)
A protocol for browsing and sharing genome sequence annotations across the Internet that allows users to search and compare annotations from several sources.
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Ensemble provides a DAS reference server with access to a wide range of specialist annotations of the human genome.
DASH
Dynamic Allele Specific Hybridisation.
Data cleaning
A process by which automated or semi-automated algorithms are used to process experimental data, including noise, experimental errors and other artifacts. This is useful to generate and store high-quantity data for use in subsequent analysis. Data cleaning is essential for high-throughout sequencing where compression or other experimental artifacts limit the amount of sequence data generated from each sequencing data generated from each sequencing run or read.
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D gene
A small segment of immunoglobulin heavy chain and T-cell receptor DNA that codes for the third hypervariable region of most receptors.
D loop
1. A DNA structure in which there is localized denaturation of the duplex or displacement of one strand giving rise to a D-shaped structure. The structure is stabilized by binding to single-strand binding proteins. 2. A region within mitochondrial DNA in which a short segment of RNA is paired with one of the strands of DNA displacing the original partner.
dA.dT tailing
See Complementary homopolymeric tailing.
Dabs
(single domain antibodies) Antibodies containing only one, rather that two protein chains derived from only one of the domains of the antibody structure. Dabs are based on the finding that for some antibodies, half of the antibody molecule binds to its target antigen almost as efficiently as the whole molecule.
Dabs offer several advantages: i) they can be made easily by bacteria or yeasts, ii) they provide a method to clone antibody like molecules into bacteria, and iii) they allow screening of millions of antibodies. Related ideas are single chain antigen binding technology (SCA), biosynthetic antibody binding sites (BABS), the minimum recognition units (MRUs), and complementarity determining regions (CDRs).
Data Manipulation Language (DML)
A language that enables the user to access or manipulate data such as insertion and deletion.
Data mining
The ability to query very large databases. This may be of two types top down data mining that satisfies a hypothesis, and bottom up data mining to interrogate a database to generate new hypothesis bases on rigorous statistical correlations.
Data processing
The systematic performance of operations upon data such as handling, merging, sorting, and computing. The semantic content of the original data should not be changed, although the semantic content of the processed data may be changed.
Data warehouses
Vast arrays of heterogenous biological data, stored within a single logical data repository. These are accessible to different querying and manipulation methods.
Database
A collection of data records on a computer, either in a single file or as multiple files. It is the central component of a database management system. Information of gene and protein sequences are stored in databases. These include the GenBank by NIH, EMBL, a European database, SWISS-PROT that translates nucleic acid sequence data to protein data and the DNA Database of Japan (DDBJ).
Database homology search
Comparison of the sequence from a subclone to the sequences in a sequence database. This helps to identify regions of homology to a previously cloned gene.
Database managament system (DBMS)
A software suite that includes a database and the utilities the necessary to organise, search, and update it, maintain data security and control access.
Database schema
A network of tables and relationships between them take make up a database. See schema.
Database search
Comparison of a query sequence with others in the databases using a computer and a search algorithm. The nucleic acid databases are GenBank and EMBL whereas PIR or SWISS-PROT is a protein sequence database. The search algorithms commonly used are BLAST and FASTA.
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