BLAZE Sensitivity

Doug Brutlag brutlag at cmgm.Stanford.EDU
Fri May 22 11:04:21 EST 1992


        The following data show that the BLAZE sequence similarity
search is capable of detecting similarities between plant and animal
hemoglobins.  By judicious choice of parameters (high PAM and low gap
penalty), BLAZE can detect 4 out of 13 plant leghemoglobins using the
human alpha globin chain as a query.  The similarity scores for these
four plant proteins are also statistically significant by an extreme
value test.

        This is very close to the sensitivity previously observed for
the FASTDB program (6 plant leghemoglobins having scores > 6 standard
deviations from the mean, Brutlag et al., CABIOS, 6, 237-245 (1990).


        BLAZE Similarity Search for Globins in Swiss-Prot 21

        Query Sequence: Database:          23,742 Sequences
        HBA_HUMAN       Swiss-Prot 21   7,866,594 Residues

Numbers below give the number of each kind of globin observed in top
600 scores.

       BLAZE    Hemogbns  Myogbns  Other    Plant
PAM    Gap Pen  Found     Found    Globins  Leg Hgs.  Total
               (469)     (79)     (56)     (13)      (617)
50     7        469       49       10       0         528

100    6        469       77       41       0         587

150    5        469       77       50       0         596

200    4        469       77       52       0         598

250    4        469       77       51       2         599
250    8        469       76       37       4         586
250    12       469       76       28       1         574
250    16       469       76       24       0         569
250    20       469       76       23       0         568




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