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Báo cáo khoa học: Helicobacter pylori acidic stress response factor HP1286 is a YceI homolog with new binding specificity

HP1286 fromHelicobacter pyloriis among the proteins that play a relevant role in bacterial colonization and persistence in the stomach. Indeed, it was demonstrated to be overexpressed under acidic stress conditions, together with other essential virulence factors. Here we describe its crystal structure, determined at 2.1 A˚ resolution. | ễFEBS Journal Helicobacter pylori acidic stress response factor HP1286 is a Ycel homolog with new binding specificity Lorenza Sisinni1 2 Laura Cendron1 2 Gabriella Favaro3 and Giuseppe Zanotti1 2 1 Department of BiologicalChemistry University of Padua Italy 2 Venetian Institute of Molecular Medicine VIMM Padua Italy 3 Department of Chemistry University of Padua Italy Keywords erucamide fatty-acid binding proteins Helicobacter pylori lipid binding lipocalins Correspondence G. Zanotti Department of Biological Chemistry University of Padua Viale Colombo 3 35131 Padua Italy Fax 39 049 8073310 Tel 39 049 8276409 E-mail giuseppe.zanotti@unipd.it Website http tiresia.bio.unipd.it zanotti Database The coordinates and structure factors have been deposited in the Protein Data Bank http www.pdb.org for immediate release with ID code 3HPE Received 23 December 2009 revised 27 January 2010 accepted 4 February 2010 doi 10.1111 j.1742-4658.2010.07612.x HP1286 from Helicobacter pylori is among the proteins that play a relevant role in bacterial colonization and persistence in the stomach. Indeed it was demonstrated to be overexpressed under acidic stress conditions together with other essential virulence factors. Here we describe its crystal structure determined at 2.1 A resolution. The molecular model a dimer characterized by two-fold symmetry shows that HP1286 structurally belongs to the Ycel-like protein family which in turn is characterized by the lipocalin fold. The latter characterizes proteins possessing an internal cavity with the function of binding and or transport of amphiphilic molecules. Surprisingly a molecule of erucamide was found bound in the internal cavity of each monomer of recombinant HP1286 cloned and expressed in an Escherichia coli heterologous system. The shape and length of the cavity indicate that at variance with other members of the family HP-YceI has a binding specificity for amphiphilic compounds with a linear chain of about 22 carbon atoms. These .