title: Structural determinants of the interaction between the Haemophilus influenzae Hap autotransporter and fibronectin.
abstract: Haemophilus influenzae is a Gram-negative cocco-bacillus that initiates infection by colonizing the upper respiratory tract. Hap is an H. influenzae serine protease autotransporter protein that mediates adherence, invasion and microcolony formation in assays with human epithelial cells and is presumed to facilitate the process of colonization. Additionally, Hap mediates adherence to fibronectin, laminin and collagen IV, extracellular matrix (ECM) proteins that are present in the respiratory tract and are probably important targets for H. influenzae colonization. The region of Hap responsible for adherence to ECM proteins has been localized to the C-terminal 511 aa of the Hap passenger domain (HapS). In this study, we characterized the structural determinants of the interaction between HapS and fibronectin. Using defined fibronectin fragments, we established that Hap interacts with the fibronectin repeat fragment called FNIII(1-2). Using site-directed mutagenesis, we found a series of motifs in the C-terminal region of HapS that contribute to the interaction with fibronectin. Most of these motifs are located on the F1 and F3 faces of the HapS structure, suggesting that the F1 and F3 faces may be responsible for the HapS-fibronectin interaction.
authors.affiliation: Department of Pediatrics and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Nicole A
authors.initials: NA
authors.lastname: Spahich
authors.affiliation: Department of Pediatrics and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Roma
authors.initials: R
authors.lastname: Kenjale
authors.affiliation: Department of Pediatrics and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: McCann
authors.affiliation: State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui-Jin Hospital affiliated to Shanghai JiaoTong University School of Medicine, 197 Ruijin Er Road, Shanghai 200025, PR China.
authors.forename: Guoyu
authors.initials: G
authors.lastname: Meng
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Ohashi
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC, USA.
authors.forename: Harold P
authors.initials: HP
authors.lastname: Erickson
authors.affiliation: Department of Pediatrics, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Joseph W
authors.initials: JW
authors.lastname: St Geme
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D005353:Fibronectins / Q000235:genetics* / Q000378:metabolism*; D006193:Haemophilus influenzae / Q000502:physiology*; D006801:Humans; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D025941:Protein Interaction Mapping; D012697:Serine Endopeptidases / Q000235:genetics* / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D005353:Fibronectins; C091552:Hap protein, Hemophilus influenzae; D012697:Serine Endopeptidases