Database sequence-search

When the Arabidopsis Expressed Sequence Tag (EST) Database was searched with the tomato fmit Psubunit protein sequence two related cDNAs were identified (Figure 11). cDNA 2 is near full length and has been completely sequenced, cDNA 1 has also been sequenced but currently lacks approximately 100 amino acids of coding region. The two Arabidopsis cDNAs are 81% identical at the protein level and have lower identity to the protein encoded by tomato gene 1, 64 and 63% for cDNA 1 and cDNA 2, respectively. However, both cDNAs encode... 

The lower part shows information ofselected protein sequence. The small table shows the results of sequence search against UNIPROT(Swiss-prot/TrEMBL), nr.aa, and UniGene database see Subheading 2, items 2 and 4) using BLAST. 

There are different classes of protein sequence databases. Primary and secondary databases are used to address different aspects of sequence analysis. Composite databases amalgamate a variety of different primary sources to facilitate sequence searching efficiently. The primary structure (amino acid sequence) of a protein is stored in primary databases as linear alphabets that represent the constituent residues. The secondary structure of a protein corresponding to region of local regularity (e.g., a-helices, /1-strands, and turns), which in sequence alignments are often apparent as conserved motifs, is stored in secondary databases as patterns. The tertiary structure of a protein derived from the packing of its secondary structural elements which may form folds and domains is stored in structure databases as sets of atomic coordinates. Some of the most important protein sequence databases are PIR (Protein Information Resource), SWISS-PROT (at EBI and ExPASy), MIPS (Munich Information Center for Protein Sequences), JIPID (Japanese International Protein Sequence Database), and TrEMBL (at EBI). ... 

Most protein families are characterized by several conserved motifs. The PRINTS hngerprint database was developed to use multiple conserved motifs to build diagnostic signatures of family membership (Attwood et al., 1998). If a query sequence fails to match all the motifs in a given hngerprint, the pattern of matches formed by the remaining motifs allows the user to make a reasonable diagnosis. The PRINTS can be accessed by keyword and sequence searches at http //www.bioinf. 

Figure 12.17. Search a sequence against Blocks database. The search of cod alcohol dehydrogenase sequence against Blocks database returns a list of hits and pairwise alignments of blocks (only one set is shown).

An Internet link to protein sequence databases and search engines is found at www.sdsc.edu/ResTools/biotools/biotoolsl9.html and a link to Internet resources for sequence analysis is www.sdsc.edu/ResTools/biotools/biotoolsl.html. 

The GENEMAN application is a tool that allows you to access and search for DNA and protein sequences located in six different biological databases. The search for a sequence of interest can be made as broad or restrictive as desired, since there are 12 different fields (definition, reference, source, accession number, etc.) to choose from when the search is performed. In addition to performing database searches to find sequences of interest, GENEMAN allows you to search the database for sequences that share homology with the sequence of interest, or for entries that contain a particular conserved sequence. Any number of different DNA or protein sequences found in these databases can be isolated and stored as a sequence file for later analysis. 

Figure 2. Workflow of an LC-MS/MS experiment. A mixture of peptides from a protein sample digest is separated by reversed-phase chromatography on a nano-flow HPLC. The peptides elute from the RP column and are ionized by an electrospray source. In the first stage of mass spectrometry, m/z values and charge states for each precursor ion are determined and the most abundant precursor ions are selected for analysis in the second stage. The ions are then fragmented with by collision-induced dissociation (CID) a gas to produce fragment ions which are detected. Using the mass (from MS-1) and sequence information (from MS-2) protein sequence databases are searched to provide peptide identifications and protein matches.

The National Center for Biotechnology Information (NCBI). Located at the National Library of Medicine in Bethesda, MD, USA. The home of the GenBank DNA sequence database PubMed literature search engine sequence search tools (e.g., PSI-BLAST) genomic sequence navigation tools. A substantial repository of resources in all areas of bioinformatics. 

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