Binding of Duck Carboxypeptidase D to Duck Hepatitis B Virus

The initial step in viral infection is binding of the particle to a receptor on the host-cell surface. The specificity of this process is the outcome of an evolutionary adaptation of the pathogen to its host. Receptor recognition frequently determines host specificity and tissue tropism. For enveloped viruses, binding is followed by fusion of the virus membrane with either the plasma or an endosomal membrane. The general mechanism of membrane fusion involves conformational changes of virus-encoded fusion proteins, leading to physical approximation and finally merging of viral and cellular membranes. A detailed understanding of receptor binding and membrane fusion is not only of general interest for molecular virologists, it also provides the basis for therapeutics that interfere with infection.