You can turn on the low complexity filter under Algorithm parameters. If you click on the number of bits
following each Blast hit, you will see the alignment of the query sequence (the one you provided) and the
hit sequence (the one in the database, it is marked as Sbjct in the alignment). You might notice that some
parts of the sequence are printed with greyish low case letters. These are so-called low-complexity
regions, which are ignored when computing the alignment score of the hit. For more information, see your
reader. Why is it useful to ignore such regions when computing the E-value? Exact amino acid matches in
the alignment are marked with the amino acid letter, and "pretty good" matches are marked with +
(e.g. amino acids with high values in BLOSUM or another scoring matrix, which probably have comparable
properties). Remember the colours in the ClustalW alignments of the previous web exercises.