IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Structurefunction prediction of Glycosylphosphatidylinositol (GPI)anchored fungal Aspartic peptidases
Autor/es:
MARÍA VICTORIA REVUELTA*, FACUNDO ORTS*, ARJEN TEN HAVE*
Lugar:
Quilmes
Reunión:
Congreso; 1er Congreso Argentino de Bioinformática y Biología Computacional; 2010
Institución organizadora:
Asociación Argentina de Bioinformática y Biología Computacional
Resumen:
Background Fungi secrete a number of hydrolases typically somehow involved in nutrient provision and competition. Plant pathogenic fungus Botrytis cinerea secretes a rather high activity of Aspartic Peptidase (AP). Recently we showed that it contains 14 putative AP encoding genes. Surprisingly, we found five sequences with a GPI anchor motif. A phylogenetic tree of fungal APs showed "ancient" clades comprising sequences from both basidio and ascomycetes as well as a large number of ascomycetespecific clades. GPIanchored APs appear in an ancient clade as well as in two related ascomycetespecific clades (referred to as Yapsin clades). We wonder what this means in terms of function and started a stucturefunction prediction analysis directed at substrate specificity. Results Data mining and phylogenetic analysis were performed mainly directed at the three clades of interest. A Consurf model of the classic AP pig pepsin shows the highly conserved binding cleft is surrounded by higly variable flaps. We performed a number of Consurf analyses using fungal APs sampled from our large multiple sequence alignment using different selection criteria (e.g GPIAPs, ancientAPs, Yapsins). We compared the flap regions in order to obtain insight in substrate specificity. A comparison between sequences from the ancient GPIAPs and the yapsin superclade with DIVERGE identified residues likely to be involved in branch formation. A similar analysis between sequences derived from subclades of the yapsin superclade was hampered by their proximity in the tree and a lack of sequence data Other analyses such as a comparison of known structures (SAMO), a surface and a coevolution analysis (APs consist of two homologous lobes) as well as the integration of the obtained data is in progress. A final analysis in which mature proteases will be compared with inactive zymogens will be initiated. Conclusions Eukaryotic APs form interesting subjects for structurefunction prediction since they show high sequence variability, probably as a result of high structure variablity in the general substrate, protein. The phylogeny indicates specialization of sequences. Despite many public fungal genome sequences, it remains difficult to obtain clear indications regarding substrate specificity. The ancient clade GPIAPs show clear differences with respect to yapsins, which allows for speculation regarding their physiological function. Differences among the yapsins are more difficult to obtain. More sequences and other types of analyses will have to be included in order to obtain predictions regarding possible substrates of specific APs which might eventually be tested using molecular docking.