Human and Clinical Genetics  -  LUMC©

Sequence search example

(last modified December 18, 2002)


  1. go to the NCBI homepage  -  alternatives EBI (Europe),  DDBJ (Japan)

  2. under "SEARCH" select "LocusLink"

  3. search for syntrophin  (query "syntrophin")

  4. open the human alpha1 syntrophin link  (locus 6640)

  5. under "NCBI Reference Sequences (RefSeq), Protein" select the link to the protein sequence (NP_003089)

  6. under "Display" change "Default View" to "FASTA" and click "Display"

  7. select (highlight) the protein sequence and copy it (right mouse button, "Copy")

  8. go to the NCBI homepage ("Back" button or "NCBI" top left corner)

  9. select "BLAST" (middle blue line)

  10. under "Protein BLAST" select "Standard protein-protein BLAST [blastp]

  11. "Paste" the human alpha-syntrophin protein sequence into the "Search"-window (right mouse button, "Paste")

  12. perform two searches

    1. under "Choose database" select "swissprot" and under "Now:" press "BLAST!" and finally on the new page select "FORMAT!"

    2. return to the NCBI blast window, go one page back, under "Choose database" select "nr" and under "Now:" press "BLAST!" and finally on the new page select "FORMAT!"

  13. analyse the search results and note that;
    NOTE - for details on the database hits detected select the accession number (left, start of line); to see the alignment of a hit select the figure in the "Score (bits)" column
    NOTE - for a better overview it might be helpful to change the display of the results page; go to the "formatting BLAST" page, under "Alignment view" select "query-anchored with identities" and press the "FORMAT!" button. The display of the results page will now change



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J.T. den Dunnen