03706nam a2200313 a 450000100080000000500110000800800410001910000220006024501390008226001800022130000190040150000200042052026750044065000190311565000130313465000230314765300170317065300200318765300320320765300150323970000210325470000180327570000160329370000170330970000150332670000160334170000160335770000190337315762702020-01-15       2009    bl uuuu     u00u1 u    #d1 aNESHICH, I. A. P.  aXylella fastidiosa hexameric pilus retraction motor PILT interfaces are maintained by non-hydrophobic contacts.h[electronic resource]  aIn: INTERNATIONAL CONFERENCE OF THE BRAZILIAN ASSOCIATION FOR BIOINFORMATICS AND COMPUTATIONAL BIOLOGY, 5., 2009, Angra dos Reis. Abstracts book... Angra dos Reis: ABBCBc2009  aNão paginado.  aX-Meeting 2009.  aXylella fastidiosa (Xf) causes CVC and Pierce?s Disease (affecting citrus and grape). Xf colonizes the xylem vessels in plants. Pathogenicity of the Xf are related to ability to move within the xylem. Avirulent strains rarely move from the inoculation point. Xf has proteins involved in type IV pili, which cause the twitching motility - a form of surface-associated movement. Satyshur and coworkers had solved four structures from PilT proteins (PDB codes: 2GSZ, 2EWV, 2EWW and 2EYU) from a hyperthermophilic organism, Aquifex aeolicus (Aa). PilT is a hexameric ATPase from a subgroup of the bacterial type II/type IV secretion systems, with two major domains: the Nterminal Domain (NTD) and the C-Terminal Domain (CTD) which contains the ATPase core. The importance of polar and charged CTDn: NTDn+1 interface interactions to retraction motion was discussed. Through site-directed mutagenesis on Pseudomonas aeruginosa PilT, they demonstrated that some residues are crucial to protein function, half of them (D29, R95 and R207) located on interface region. The Xf PilT has 68% of similarity and 49% of identical aminoacids to Aa). We modelled each Xf PilT chain. We analyzed the hexameric structure of Aa Pilt (PDB code: 2GSZ) and Xf PilT hexamer model (named here as 2HXF) using Blue Star STING platform. By analysis of Interface Forming Residues (IFR), we found that there was a significant difference among the interfaces: Xf PilT interfaces area occupied mainly by charged amino acids. This does not hold for the free surfaces (molecular surface without interfaces). In 2GSZ the interface area is occupied by hydrophobic and polar AA; In addition, the interfaces have less charged AA than free surface. The Aa PilT interfaces are more hydrophobic when compared to Xf PilT. The number and energies of contacts established between IFRs in 2HXF are higher than 2GSZ, suggesting that Xf PilT interfaces are more stable. Apparently, the most important IFRs (which establish most energetic contacts at the surface) are conserved within Proteobacteria and Aquificae PilTs (Clustalw alignment data). Thus, we suggest that the difference among amino acid composition of interfaces between Xf PilT and Aa PilT reflect their crucial importance on successful host infections across the Proteobacteria. We hypothesize here that similarities found in primary sequence alignment could be maintained at 3D level, indicating a possible higher selective pressure on these locations in Proteobacteria (as compared to the Aa PilT). We also suggest that these residues, crucially important to protein functionality, might serve as potential targets to eliminate bacteria pathogenicity.  aBioinformatics  aProteins  aXylella Fastidiosa  aAminoácidos  aBioinformática  aContatos não hidrofóbicos  aProteínas1 aMORAES, F. R. de1 aMARANGONI, S.1 aMARTINS, D.1 aSALIM, J. A.1 aMAZONI, I.1 aMANCINI, A.1 aNESHICH, G.1 aJARDINE, J. G.