Combining single-walled carbon nanotubes (CNT) with biological molecules provides a route to novel nanoscale materials with many promising applications in nanotechnology and nanomedicine. Recent experiments show that CNTs covalently functionalized with the coxsackie-adenovirus receptor (CAR) serve as biosensors capable of specifically recognizing Knob proteins from the adenovirus capsid. These experiments suggest that CAR retains its biologically active form when bound to CNT, but a detailed understanding of the structural changes that occur within CAR after CNT attachment is lacking. To address this, we have performed all-atom classical molecular dynamics (MD) simulations of CAR and the CAR-Knob complex in aqueous solution alone and also when covalently linked to CNT. The MD results show that the CNT damps structural fluctuations in CAR and reduces the internal mobility of the protein. However, CNT induces very little structural deformation and does not affect CAR's ability to specifically bind Knob. This MD study verifies that CAR retains its biological functionality when attached to CNT and provides a computational approach to rationalize nanobiosensing devices.