title: Crystal structure of the receptor-binding domain of adenovirus type 5 fiber protein at 1.7 A resolution.
abstract: BACKGROUND
  Adenoviral infection begins with the binding of virion to the surface of host cells. Specific attachment is achieved through interactions between host-cell receptors and the adenovirus fiber protein and is mediated by the globular carboxy-terminal domain of the adenovirus fiber protein, termed the carboxy-terminal knob domain.
  
  
  RESULTS
  The crystal structure of the carboxy-terminal knob domain of the adenovirus type 5 (Ad5) fiber protein has been determined at 1.7 A resolution. Each knob monomer forms an eight-stranded antiparallel beta-sandwich structure. In the crystal lattice, the knob monomers form closely interacting trimers which possess a deep surface depression centered around the three-fold molecular symmetry axis and three symmetry-related valleys.
  
  
  CONCLUSIONS
  The amino acid residues lining the wall of the central surface depression and the three symmetry-related floors of the valleys are strictly conserved in the knob domains of Ad5 and adenovirus type 2 (Ad2) fiber proteins, which share the same cellular receptor. The beta-sandwich structure of the knob monomer demonstrates a unique folding topology which is different from that of other known antiparallel beta-sandwich structures. The large buried surface area and numerous polar interactions in the trimer indicate that this form of the knob protein is predominant in solution, suggesting a possible assembly pathway for the native fiber protein.
authors.affiliation: Howard Hughes Medical Institute, University of Texas Southwestern Medical Center at Dallas 75235-9050.
authors.forename: D
authors.initials: D
authors.lastname: Xia
authors.forename: L J
authors.initials: LJ
authors.lastname: Henry
authors.forename: R D
authors.initials: RD
authors.lastname: Gerard
authors.forename: J
authors.initials: J
authors.lastname: Deisenhofer
mesh_terms: D000595:Amino Acid Sequence; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism; D036022:Capsid Proteins; D003196:Computer Graphics; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011991:Receptors, Virus / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D036022:Capsid Proteins; D011991:Receptors, Virus; C018315:hexon capsid protein, Adenovirus