Use of multiple profiles corresponding to a sequence alignment enables effective detection of remote homologues.
BACKGROUND
Position specific scoring matrices (PSSMs) corresponding to aligned sequences of homologous proteins are commonly used in homology detection. A PSSM is generated on the basis of one of the homologues as a reference sequence, which is the query in the case of PSI-BLAST searches. The reference sequence is chosen arbitrarily while generating PSSMs for reverse BLAST searches. In this work we demonstrate that the use of multiple PSSMs corresponding to a given alignment and variable reference sequences is more effective than using traditional single PSSMs and hidden Markov models.


RESULTS
Searches for proteins with known 3-D structures have been made against three databases of protein family profiles corresponding to known structures: (1) One PSSM per family; (2) multiple PSSMs corresponding to an alignment and variable reference sequences for every family; and (3) hidden Markov models. A comparison of the performances of these three approaches suggests that the use of multiple PSSMs is most effective.


BACKGROUND
ns@mbu.iisc.ernet.in.
Anand
B
B
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
Gowri
V S
VS
Srinivasan
N
N
D000465:Algorithms; D000595:Amino Acid Sequence; D003198:Computer Simulation; D020869:Gene Expression Profiling / Q000379:methods; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D016415:Sequence Alignment / Q000379:methods*; D020539:Sequence Analysis, Protein / Q000379:methods*; D017386:Sequence Homology, Amino Acid