| Use Entrez to find the C-terminal region (approximately
215 residues) of human BRCA1 (SWISS-PROT accession number P38398). Search
the NR protein database with this sequence using PSI-BLAST. Save your search
results. Now perform a second iteration. Compare your new search
results. Some sequence alignments from the second search have higher
scores than the same sequence alignment obtained from the first search.
Why? Alternatively, some sequence alignments from the second search have lower
scores than the same sequence alignments obtained from the first search.
Why? |