FASTA

Pearson W R 1990, Rapid and Sensitive Sequence Comparison with FASTP and FASTA. Methoc Enzymology 183 63-98. 

The FastA results show that the sequence is 47% identical over the entire length to the mitochondrial nuclease from S. cerevisiae ... 

To improve this unsatisfying situation, many bioinformatics sites construct nonredundant databases from a number of component databases, or they use external nonredundant databases, e.g., OWL (Bleasby et al., 1994). Both strategies considerably improve the situation for the end user, but they require the time- and resource-consuming maintenance of multiple databases or the acceptance of a certain time lag between creation of an entry and its appearance in the nonredundant database. Furthermore, both strategies lead to a loss of information in the individual entry owing to the diversity of database formats. Whereas OWL preserves most information of an entry and some of its structure, the NRDB program requires a conversion of the component databases to FASTA format, which contains only one description line per entry. 

SPTR is distributed in three files sprot.dat.Z, trembl.dat.Z, and trembl new.dat.Z. These files are, as indicated by their Z extension, Unix compress format files, which, when decompressed, produce ASCII files in SWISS-PROT format. Three others files are also available (sprot.fas.Z, trembl.fas.Z, and trembl new.fas.Z), which are compressed fasta format sequence files that are useful for building the databases used by FASTA, BLAST, and other sequence similarity search programs. These files should not be used for other purposes, because all annotation is lost when using this format. The SPTR files are stored in the directory /pub/databases/sp tr nrdb on the EBI FTP server (ftp.ebi.ac.uk) and in the directory /databases/sp tr nrdb on the ExPASyFTP server (ftp. expasy.ch). 

How does one go about finding all of the relevant proteins in a database once it has been decided to carry out an analysis of an entire protein family The simplest approach is to use similarity search software such as SSEARCH or FASTA (Smith and Waterman, 1981 Pearson and Lipman, 1988) or BLAST (Altschul et al, 1997) with the amino acid sequences of one or two well-known members of the family as queries. The problem is initially the same as that of identifying all proteins that are homologous to a family of proteins, although with some important practical differ-... 

Multiple alignments of repeats are constructed in an iterative manner. The initial alignment is based on definitions from determined protein structures or else from the literature. In the initial database search step, a profile constructed from the multiple alignment is compared with a sequence database. Top scoring sequences are considered using complementary approaches such as PSI-BLAST and FASTA to provide the two thresholds minimum E value and minimum number of repeats per protein required. After one or two iterations, the final alignment and the thresholds are stored in the SMART database to allow the detection of repeats in any sequence. 

SNP homology and similarity searching SNP-Fasta http //www.ebi.ac.uk/snpfasta3/ Searching SNPs with the Fasta server for homology and similarity... 

Table 1. Cellulase catatytic domain families, organized by similarity scores as determined successive FastA searches ...

Homologous proteins of the CYP superfamily with known structure serve as the templates for homology modeling. The sequence similarities and/or identities between the template and target proteins should be as high as possible. Several search methods such as FASTA (40) or BLAST (41) are available to retrieve template homologs from the PDB (Protein Data Bank) (42). 

Pearson, W. R. (1990) Rapid and sensitive sequence comparison with FASTP and FASTA. Methods Enzymol. 183, 63-98. 

Another useful structure tool is RasMol (or RasMac). This will allow you to view the detailed structure of a protein and rotate it on coordinates so you can see it from all perspectives. A hyperlink to RasMol is present under the View Structure function just above Chime. You may need to study RasMol instructions provided under Help, or you may use a Ra.s Mol tutorial listed in Table El.2. Another useful protein viewer is tin-Swiss-Protein Pdv Viewer (Table El.2). BLAST is an advanced sequence similarity tool available at NCBI. To access this, go to the NCBI home page (www.ncbi.nlm.nih.gov) and click on BLAST. Then click on Basic BLAST search to obtain a dialogue box into which you may type the amino acid sequence of human a-lactalbumin. This process may be stream lined by downloading the amino acid sequence in FASTA format into a file and transferring the fde into the BLAST dialogue box. BLAST will provide a list of proteins with sequences similar to the one entered. 

Study the nucleotide sequence for the gene coding for human a-lactalbumin. Hint Begin at the NCBI home page and enter Entrez. Click on Nucleotides and do a search on human a-lactalbumin. Review the GenBank report for the position of introns and exons. Obtain a FASTA report, transfer (download) the files, and complete a BLAST search for related sequences. 

BLAST Chime Entrez (NCBI) FASTA GenBank (NCBI) Molecules R Us RasMol (Ras Mac) SRS (EMBL) Searches for similar protein and nucleic acid sequences Protein structures on moving 3D coordinates Sequence retrieval system for cross-referencing databases Searches for similar protein sequences Database of gene sequences Provides coordinates for protein 3D structure and manipulation Provides coordinates for protein 3D structure and manipulation Sequence retrieval system for cross referencing databases... 

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