Classification of protein targeting sequences by
self-organizing feature maps
Schneider, G. 
F.Hoffmann-La Roche, 
Pharmaceuticals Division, 
Molecular Design & Bioinformatics, 
CH-4070 Basel, Switzerland
Much information about the targeting pathway of proteins is 
contained in the N-terminal part of protein precursor sequences. 
N-terminal targeting signals directing a newly synthesized 
protein towards organelles or the secretory route were analyzed 
to further understand and visualize these characteristic sequence 
features. Self-organizing neural networks were developed for this 
purpose, which were able to perform a non-linear projection of 
the multi-dimensional sequence space onto a two-dimensional map. 
The maps generated show a clear separation of the different types 
of targeting sequences and allow for an interpretation of the 
features extracted by the network. It turns out that 
physicochemical properties of the N-terminal fragments of protein 
precursor sequences contribute to the targeting signal. This 
finding is a consequence of a new way of sequence representation 
in terms of correlations of residue properties. This technique is 
presented, and both specific advantages and limitations of 
pattern recognition by self-organizing networks are discussed.
Schneider, G. (1997) Concepts in molecular bioinformatics. BIF 
Futura 12, 87-97.
Schneider, G., Sjoling, S., Wallin, E., Wrede, P., Glaser, E., 
von Heijne, G. (1998) Feature extraction from mitochondrial 
signal peptidase cleavage sites. Proteins: Struct. Funct. 
Genet. (January 1998 issue), in press.
| LOCATION | DATE | TIME | 
| Lecture Hall II | Sunday, April 5 | 06:20 pm |