NCBI is a nonredundant database compiled by the NCBI (National Center for Biotechnology Information) as a protein database for Blast searches. It contains nonidentical sequences from GenBank CDS translations, Protein Data Bank (PDB), SwissProt, Protein Information Resource (PIR), and Protein Research Foundation (PRF).
http://blast.ncbi.nlm.nih.gov/Blast.cgi
A typical NCBI title line follows:
>gi|70561|pir||MYHO myoglobin - horse_i|418678|pir||MYHOZ myoglobin - common zebra (tentative sequence) [MASS=16950]
FASTA ID:
Accession#:gi70561
Description:myoglobin - horse_i