Appl Microbiol Biotechnol (2006) 70: 2–11
DOI 10.1007/s00253-005-0270-9
MINI-REVIEW
Matthias Paschke
Phage display systems and their applications
Received: 31 August 2005 / Revised: 17 November 2005 / Accepted: 17 November 2005 / Published online: 20 December 2005
# Springer-Verlag 2005
Abstract Screening phage display libraries of proteins and
peptides has, for almost two decades, proven to be a
powerful technology for selecting polypeptides with
desired biological and physicochemical properties from
huge molecular libraries. The scope of phage display ap-
plications continues to expand. Recent applications and
technical improvements driving further developments in
the field of phage display are discussed.
Introduction
Twenty years ago, Smith (1985) established a method for
presenting polypeptides on the surface of filamentous
phage (Fig. 1), a virus that infects Escherichia coli.In
contrast to other phages (e.g., T4), filamentous bacterio-
phages (e.g., M13) replicate and assemble without killing
the host cell. Since the pioneering work of Smith, phage
display technology based on these “friendly” phages has
matured into a widely used technique for selecting peptides
and proteins with desired functions and properties from
molecular libraries.
The principle underlying all phage display systems is the
physical linkage of a polypeptide's phenotype to its cor-
responding genotype. In practice, the proteins or peptides
to be displayed are usually expressed as fusions with the
phage coat protein pIII or pVIII (display on other coat
proteins is described in Sidhu 2001). Such fusion proteins
are directed to the bacterial periplasm or inner cell mem-
brane by an appropriate signal sequence that is added to
their N terminus (Endemann and Model 1995). During the
phage assembly process the fusion proteins are incor-
porated into the nascent phage particle. The genetic
information encoding the displayed fusion protein is
packaged inside the same phage particle in the form of a
single-stranded DNA (ssDNA) molecule. Hence, the
genotype–phenotype coupling occurs before the phages
are released into the extracellular environment, ensuring
that phages produced from the same bacteria cell clone are
identical. In this manner, huge phage display libraries
containing up to 10
10
individual members can be created
from batch-cloned gene libraries. Most applications of
phage display libraries aim at identifying polypeptides that
bind to a given target molecule. The enrichment of phages
that present a binding protein (or peptide) is achieved by
affinity selection of a phage library on the immobilized
target. In this “panning” process, binding phages are cap-
tured whereas nonbinding ones are washed off. In the next
steep, the bond phages are eluted and amplified by re-
infection of E. coli cells. The amplified phage population
can, in turn, be subjected to the next round of panning. It is
quite typical that phage library screening entails several
(mostly three) consecutive rounds of panning and phage
amplification before the selected phage and the polypeptide
that they present are individually analyzed. Put simply, the
selection from phage display libraries is a cyclic process of
selective enrichment and amplification.
This review focuses on the phage display and selection
of functional proteins. Recent advances and applications of
phage display will be discussed.
Classification of phage display systems
Phage display systems can be grouped into two classes on
the basis of the vector system used for the production of
phages.
True phage vectors are directly derived from the genome
of filamentous phage (M13, f1, or fd) and encode all the
proteins needed for the replication and assembly of the
filamentous phage (see Russel 1995; Marvin 1998 for
reviews on phage biology). In these vectors, the library is
ether cloned as a fusion with the coat protein originally
M. Paschke (*)
Institut für Biochemie, Charité-Universitätsmedizin Berlin,
Monbijoustrasse 2A,
10117 Berlin, Germany
e-mail: matthias.paschke@charite.de
Tel.: +49-30-450528147
Fax: +49-30-450528909