text: user1191: Can anyone explain me, why I don't find a specific protein with a blast that was took before from the NCBI refseq database?
  Specifically, I was trying to blast the protein with the accession number "NP_420767" and its sequence, respectively, however that protein does not show up in the results. It not only happens when the standard options are chosen, but also, when "Reference proteins (refseq_protein)" as database in the blast options is selected.
  I am really puzzled by that.. Shouldn't blast show the initial refseq entry in the results list as it is part of the refseq database and has the same sequence?
  
  user581: NP_420767 is represented by the non-redundant refSeq protein WP_010919826, which has the same amino acid sequence. This is not very clearly annotated, but if you scroll down to the sequence in the GenPept entry for NP_420767, you'll see the following:
  CONTIG      join(WP_010919826.1:1..799)
  
  See here for more info.
  
original_text: 1191: <p>Can anyone explain me, why I don't find a specific protein with a blast that was took before from the NCBI refseq database?</p>
  
  <p>Specifically, I was trying to blast the protein with the accession number "NP_420767" and its sequence, respectively, however that protein does not show up in the results. It not only happens when the standard options are chosen, but also, when "Reference proteins (refseq_protein)" as database in the blast options is selected.</p>
  
  <p>I am really puzzled by that.. Shouldn't blast show the initial refseq entry in the results list as it is part of the refseq database and has the same sequence?</p>
   581: <p>NP_420767 is represented by the non-redundant refSeq protein WP_010919826, which has the same amino acid sequence. This is not very clearly annotated, but if you scroll down to the sequence in the GenPept entry for NP_420767, you'll see the following:</p>
  
  <pre><code>CONTIG      join(WP_010919826.1:1..799)
  </code></pre>
  
  <p>See <a href="https://www.ncbi.nlm.nih.gov/refseq/about/nonredundantproteins" rel="nofollow noreferrer">here</a> for more info.</p>
  