Crystal structure of the receptor-binding domain of adenovirus type 5 fiber protein at 1.7 A resolution

Structure. 1994 Dec 15;2(12):1259-70. doi: 10.1016/s0969-2126(94)00126-x.


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.

MeSH terms

  • Amino Acid Sequence
  • Capsid / chemistry*
  • Capsid / metabolism
  • Capsid Proteins*
  • Computer Graphics
  • Crystallography, X-Ray
  • Molecular Sequence Data
  • Protein Conformation
  • Receptors, Virus / metabolism*
  • Sequence Alignment


  • Capsid Proteins
  • Receptors, Virus
  • hexon capsid protein, Adenovirus