Superdomains in the protein structure hierarchy: The case of PTP-C2 |
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Authors: | Donald T Haynie Bin Xue |
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Affiliation: | 1Department of Physics, School of Natural Sciences and Mathematics, College of Arts and Sciences, University of South Florida, Tampa, Florida, 33620;2Department of Cell Biology, Microbiology, and Molecular Biology, School of Natural Sciences and Mathematics, College of Arts and Sciences, University of South Florida, Tampa, Florida, 33620 |
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Abstract: | Superdomain is uniquely defined in this work as a conserved combination of different globular domains in different proteins. The amino acid sequences of 25 structurally and functionally diverse proteins from fungi, plants, and animals have been analyzed in a test of the superdomain hypothesis. Each of the proteins contains a protein tyrosine phosphatase (PTP) domain followed by a C2 domain. Four novel conserved sequence motifs have been identified, one in the PTP domain and three in the C2 domain. All contribute to the PTP-C2 domain interface in PTEN, a tumor suppressor, and all are more conserved than the PTP signature motif, HCX3(K/R)XR, in the 25 sequences. We show that PTP-C2 was formed prior to the fungi, plant, and animal kingdom divergence. A superdomain as defined here does not fit the usual protein structure classification system. The demonstrated existence of one superdomain suggests the existence of others. |
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Keywords: | domain evolution hierarchy protein structure superdomain |
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