Prediction of homology and divergence in the secondary structure of polypeptides.
AUTOR(ES)
Pongor, S
RESUMO
A quantitative procedure is described for the comparison of secondary structure of homologous proteins. Standard predictive methods are used to generate probability profiles from pairs of homologous amino acid sequences; correlation coefficients (R) are then computed between each pair of amino acids for alpha-helix (R alpha), extended structure (R beta), turn (R(t)), and coil (R(c)). R values are >0.2 for correctly aligned homologous sequences. Unrelated or incorrectly aligned sequences give R values near zero. Lack of correlation for a segment of otherwise well-correlated sequences is used to identify structural divergence, which is then evaluated graphically by using difference profiles. A combination of these techniques correctly predicts secondary structural differences between melittin or beta-endorphin and their respective synthetic analogs. The method is potentially useful to describe evolutionary changes in protein secondary structure as well as in the design of peptide analogs.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=397039Documentos Relacionados
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