Overview of the Manifold VNPs Used in Nanotechnology - Viral Nanoparticles: Tools for Materials Science and Biomedicine - page 14

sense is the complementary strand; it is also referred to as antisense and
requires transcription into the positive-sense strand prior to translation into
a protein.
For detailed information about the genome organization and structure
of viruses see the following databases: Description of Plant Viruses database
(DPV; http://www.dpvweb.net), the Universal Database of the International
Committee on Taxonomy on Viruses (ICTV; http://www.ncbi.nlm.nih.gov/
ICTVdb), and the Virus Particle ExploreR Database (VIPER; http://viperdb.
scripps.edu).
Chimeric virus strategies used in nanotechnology. Because virus

genomes are relatively small, many virus genomes have been completely
sequenced, and detailed knowledge about their genomic properties is
available (nucleic acid sequences are available at the National Center for
Biotechnology Information database; http://www.ncbi.nlm.nih.gov/.) This
led to the development of chimeric virus technology. A virus chimera refers to
a genetically modified version of the wild-type or native virus. Chimeric viral
particles, for example, have been used for vaccine development. Chimeric
virus technology allows genetic insertion of an antigenic peptide into the
coat protein sequence. Viral capsids consist of multiple copies of the same
coat protein; hence, the chimeric particle displays multiple copies of the
antigenic peptide sequence on its capsid surface. The multivalency of peptide
presentation and the VNP carrier may lead to an enhanced immune response
against the antigens. Vaccine strategies are discussed in Chapter 8.
In nanotechnology, chimeric virus technology is also used to fine-
tune and alter VNP surface properties. Additional amino acid side chains
can be introduced onto the capsid to allow chemical modification and the
installation of additional functionalities. For example, if a VNP does not have
any solvent-exposed Cys side chains on its exterior capsid surface, these could
be introduced using molecular cloning techniques. The thiol group of Cys
residues is an attractive target for bioconjugation chemistry because thiols
undergo facile coupling with maleimide-activated compounds, and a large
range of such compounds are commercially available. A range of Cys-added
chimeric VNPs have been synthesized, which will be mentioned throughout
this topic. The principles of chimeric virus technology and its applications for
nanotechnology are discussed in greater detail in Chapter 3.

.1. the Structure of Viruses

The structures of viruses reveal remarkable diversity (recall the complex
and unique structure of the bottle-shaped virus ABV in Chapter 1;

Fig. 1.2). The structure of viruses can be divided into four main groups:

Acidianus