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School of biological Sciences
College of Science, NTU, Singapore
A Research Institute Dedicated to
Research Excellence in Life Science

School of biological sciences
a Rising star in life sciences
When founded in 2002, the School of Biological Sciences (SBS) had a mission to make
a strong contribution to biological- and biomedical sciences. Since then, many talented
individuals from around the world and Singapore have joined SBS―scientific leaders,
researchers, PhD- and Master students, working in the two divisions of Structural Biology
and Biochemistry as well as Molecular Genetics and Cell Biology. In this publication we
celebrate recent achievements of our scientists in diverse areas such as Peptide Chemistry,
Drug Discovery, Genetics & Disease, Infectious Diseases, Protein Engineering and
Environmental Biotechnology. We hope that you enjoy this first print edition of SBS
Research and that through it you can gain a better picture of the variety of cutting-edge
research being done at SBS.
However, the magazine you are holding is only part of the story. Updated every six
months, SBS Research brings you the very latest research from SBS across a broad
spectrum in life sciences.
We hope all of you will enjoy reading SBS Research and that, over time, this publication
will help to share the entire span of research activities among ourselves, students and
partners in research and in industry.
Prof. M. Featherstone Prof. G. Grüber
Chair of SBS Associate Chair (Research) of SBS
2

Cell-permeable Peptide Nucleic Acid
Peptide nucleic acid (PNA) is a DNA
mimic with a polyamide backbone. The
high hybridizing affinity and specificity
of PNA has made it an attractive agent for
antigene and antisense research. But poor
cellular uptake is a major disadvantage
that has severely limited its use in
functional genomics and molecular
therapy. The laboratory of A/Prof
Chuan-Fa Liu (SBS, NTU) has designed
a new type of PNA analogue that has
built-in cell-permeability. In this design,
structural moieties with inherent
membrane translocation ability are built
onto PNA’s polyamide backbone without
affecting its hybridization activity. This
is achieved by introducing a guanidinebearing
peptoid-like side chain onto the
γ-N of the PNA backbone. Thus, this
novel class of nucleic acid mimics
possesses all the desired properties
expected for an ideal antigene or
antisense agent: base-pairing ability, cellpermeability,
in vivo stability and ease of
preparation due to the simplified pseudopeptide
backbone. The new PNA
analogue will be a useful geneknockdown
agent both for basic
biomedical research and therapeutic
development.
1. Chuan-Fa Liu, Yun Zeng and Xiao-Wei Lu. Peptide Nucleic Acid Monomers and Oligomers. Singapore Patent No.
169162 (date of grant 31 October 2011).
3

The Peptibody Technology for
Peptide Drug Discovery
Bioactive peptides would be excellent
drug candidates if not for their poor
pharmacokinetic profiles like very short
half-lives in vivo. A major recent
breakthrough is the advent of the socalled
“peptibody” platform technology.
In a peptibody a bioactive peptide of
interest is fused to the Fc domain of
human IgG at either the N- or Cterminus.
A fusion protein so-created has
been shown to have a dramatically
increased half-life that may last for
weeks in an animal’s body. Such
peptide-Fc fusion constructs are
therefore very useful formats for
designing peptide-based drugs, as
validated by the successful development
of the first peptide drug – Nplate®
(romiplostim) – which was discovered
by A/Prof Liu Chuan-Fa (SBS, NTU)
and colleagues while he was at Amgen.
1. C.-F Liu, U. Feige, J. C. Cheetham. Thrombopoietic compounds. US Patent #6,835,809 (date of grant 28 Dec. 2004).
4

Peptide Dendrimers As Novel Platform
for Vaccine Development
The laboratory of Prof James P. Tam
(SBS, NTU) invented a new technological
platform known as multiple antigen
peptides (MAP) or peptide dendrimers for
development of safe and effective vaccines.
In the MAP system, multiple copies of
antigenic peptides are bound to a nonimmunogenic
Lys-based dendritic scaffold.
The MAP molecules acquire proteolytic
stability, enhanced molecular recognition
by immune cells, and induction of stronger
immune responses compared with
monomeric peptides. This structure permits
controlled structure-activity relationship
studies, and is applicable for oral or nasal
delivery to elicit mucosal immune
responses. The MAP-based vaccines also
eliminate the need for the inclusion of
adjuvants found to be toxic to humans, and
avoid the adverse effects associated with
conventional vaccines (i.e., live-attenuated,
killed or inactivated pathogens), carrier
proteins and cytotoxic adjuvants.
Since the introduction of MAPs by Tam’s
research group, over 200 applications of
MAPs have been documented in the
literature. It has become a popular method
with many vaccines currently being studied
in clinical trials in the treatment for
malaria, influenza, tuberculosis and HIV.
Commercial companies specializing in
peptide reagents now offer either reagents
for synthesizing MAPs in the laboratory or
by custom synthesis services.
1. U.S. and Denmark Patents no. 398,846: A Method for Rapid and Multiple Peptide Synthesis.
2. WO Patent no. 011778: Dendritic Polymer of Multiple Antigen Peptide System Useful as Anti-Malarial Vaccine.
3. WO Patent no. 003766: Multiple Antigen Peptides for Use as HIV Vaccines.
4. U.S. Patent no. 5,580,563: Multiple antigen peptide system having adjuvant properties, vaccines prepared therefrom and
methods of use thereof.
5. U.S. Patent no. 5,229,490: Multiple antigen peptide system 5

Genome surgery for biotechnological
and medical application
Genetic manipulation of genomes is an important
component of many applications in biotechnology
and molecular medicine. Prominent examples
include generation of genetically modified cells for
the production of protein therapeutics/diagnostics,
drug testing/development and gene therapy.
However, existing gene insertion technologies
often lack desired target sequence specificity and
are mostly irreversible. These features can result in
potentially harmful genomic mutations and/or
unpredictable complications. The laboratory of
A/Prof Peter Dröge (SBS) possesses a patented,
site-specific genome insertion technology which
has found commercial application. It enables users
to express any transgenic DNA construct of
interest from a pre-determined, single genomic
docking site. Examples of potential applications of
this technology, in particular in conjunction with
our novel “in-house”-developed embryonic stem
cell pluripotency reporter system, include GMO
production, gene therapy, and drug screening.
1. Dröge, P. Sequenz-spezifische Rekombination in eukaryotischen Zellen. Patent granted in China (2004), Australia (2005)
Mexico (2006), Korea (2005) European Union (2006), Israel (2008), India (2009), Singapore (2008)
2. Dröge, P., Enenkel, B. (2002): Sequenz-specific recombination in eukaryotic cells.
3. Liu, A. O, Liang, X. J., Zhang, X. M. Sun, S, Drőge, P. (2009): Microfluidic Cell Sorter System.
4. Ghadessy, F. J., Sian,T. M., Drőge, P. (2009): Muteins of the Bacteriophage λ Integrase. PCT in 2011
6

A novel process and reagents for rapid
genetic alterations in eukaryotic cells
Sequence-specific gene silencing by short hairpin (sh) RNAs has recently emerged as an
indispensable tool for understanding gene function and a promising avenue for disease
therapies. However, a wider biomedical use of this approach is hindered by the lack of
straightforward methods for achieving uniform expression of shRNAs in mammalian cell
cultures. To this end, the group of Asst Prof Eugene Makeyev (SBS, NTU) has developed
a high-efficiency and low-background (HILO) recombination-mediated cassette exchange
(RMCE) technology that yields virtually homogeneous cell pools containing doxycyclineinducible
shRNA elements in a matter of days and with minimal efforts (1, 2). The utility
of this approach has been shown for a number of commonly used human and mouse cell
lines. Because of its technical simplicity and cost efficiency, the technology should
facilitate both low- and high-throughput shRNA-based RNA interference projects.
Moreover, a recent study by the Makeyev lab demonstrates (3) that HILO-RMCE will be
useful for a wider range of molecular and cell biology applications by allowing one to
rapidly engineer cell populations expressing essentially any transgene of interest.
1. Makeyev E.V., Khandelia P., Yap K. (2011) A novel process and reagents for rapid genetic alterations in eukaryotic cells.
US Provisional Patent Application No.: 61/504,577.
2. Khandelia P., Yap K., Makeyev E.V. (2011) Streamlined platform for short hairpin RNA interference and transgenesis in
cultured mammalian cells. Proc. Natl. Acad. Sci. USA 108, 12799-12804.
3. Dai W., Zhang G., Makeyev E.V. (2012) RNA-binding protein HuR autoregulates its expression by promoting alternative
polyadenylation site usage. Nucleic Acids Res. 40, 787-800.
7

Enzymatic Synthesis of Cyclic Dinucleotides
as Potent Immunostimulatory Agents
The cyclic dinucleotides c-di-GMP and cdi-AMP
are newly discovered bacterial
messenger molecules with potent
immunostimulatory properties. With their
potential to be used as immunologic or vaccine
adjuvants, efficient synthesis of the
dinucleotides in large quantity is essential for
research and clinical trial purposes. Currently,
c-di-GMP and c-di-AMP can be obtained by
multi-step chemical synthesis methods that are
not suitable for large scale production.
Enzymatic synthesis of c-di-GMP using
mesophilic enzymes suffers from low
production yield due to protein instability and
strong product inhibition. The laboratory of
A/Prof Zhao-Xun Liang (SBS, NTU) lab has
cloned and engineered two hyperthermophilic
enzymes: a diguanylate cyclase (tDGC) and a
diadenylate cyclase (tDAC), for the enzymatic
synthesis of c-di-GMP and c-di-AMP. The
product inhibition that previously limited
production yield of c-di-GMP was
significantly alleviated by protein engineering
in the putative regulatory inhibition site. With
the engineered enzymes, the lab demonstrated
that grams of c-di-GMP/AMP can be readily
prepared by using the procedures optimized
for enzymatic reaction and product
purification. The thermophilic enzymes are not
only highly valuable for large-scale c-di-
GMP/AMP production but also suitable for the
preparation of radioisotope-labeled c-di-
GMP/AMP derivatives.
1. Liang, Z.-X., Rao, F. (2010) Engineering of a thermophilic diguanylate cyclase for large-scale production of cyclic-di-GMP.
US Patent 1/156/826.
2. Liang, Z.-X., Pasunooti, S. (2011) Efficient enzymatic synthesis of cyclic and linear diadenosine monophosphates by thermophilic
enzymes. US Patent application No. PCT/SG2010/000060.
8

Proteolytic peptides as biomarkers for
hemoglobinopathies and other diseases
a-thalassemia
X
Protein biomarker discovery efforts are usually
hampered by the fact that most of the candidate
markers identified result from the body’s
response to diseases, rather than disease-causing
proteins themselves. This often raises serious
questions about the specificity of these candidate
markers. On the other hand, disease-causing
protein mutations, if known and easily detected,
a
b
could serve as ultimate biomarkers. However,
proteins carrying such mutations are rare and
often in low abundance, making them difficult to
be detected. The laboratory of Asst. Prof Kai
Tang (SBS, NTU) hypothesized that these
proteins are degraded by endogenous proteases
and the proteolytic peptides carrying the
mutation could be more readily detected and
serve as potential biomarkers for diseases. They
tested this hypothesis in α-thalassemia patients
with stop-codon mutations and identified a
number of proteolytic peptides. The sequence of
these peptides matched with the C-terminal
fragments of the elongated α-globin. They have
been identified in peripheral blood carrying the
Hb CS (Hb Constant Spring) or PS (Pakse)
allele, including homozygotes and heterocygotes
The researchers also found that in samples carrying HbE allele, a common Hb variant in
Southeast Asia due to mutation in beta globin chain, proteolytic peptides carrying the HbE
mutation could also be found in peripheral blood of both homozygous and heterozygous
carriers. Furthermore, proteolytic peptides from sickle cell samples carrying specific
mutations HbS and HbC can also be found in peripheral blood. When validated, the
method can be used for high-throughput screening of hemoglobinopaties or other diseases
using tandem mass spectrometry.
1. Tang, K., Sanmun, D., Fucharoen, S., Law, H. Y., Ng, I. (2011) Proteolytic peptides as biomarkers for thalassemia and other
genetic diseases, US provisional patent filed (#61/491,489).
9

Antibody as a potential component
of Blocking invasion in Malaria
Invasion
Invasion by the malaria merozoite
depends on recognition of specific
erythrocyte surface receptors by parasite
ligands. Plasmodium falciparum uses
multiple ligands, including the
reticulocyte binding protein homologues
(RHs). RH are conserved in all species
of Plasmodium and play an important
role in host cell sensing and recognition
as well as virulence. The group of Prof
Peter Preiser (SBS, NTU) has identified
the functional region of RH proteins that
mediates the initial binding of the
protein to a specific receptor on the
erythrocyte surface. Antibodies against
this domain are able to block invasion of
the merozoite efficiently. The relatively
small (334 amino acid) region of RH that
encodes the binding domain is ideal for
recombinant protein expression and can
serve as a potential component of an
invasion blocking antibody.
1. Gao, X., Preiser, P. R. Binding Domain of Plasmodium Reticulocyte Binding Proteins. Singapore Patent No. 150149 (date of
grant 8 December 2011)
2. Gao, X. Preiser, P. R. (2008) Antibodies targeting the PfRH1 binding domain inhibit invasion of Plasmodium falciparum
merozoites. PLoS Pathog. 4, e1000104
10

Bacterial Co-cultures as tools in
Environmental Biotechnology
The concept of Bioaugmentation in
Environmental Biotechnology is not new –
this involves adding microbial strains with
specialized ability, e.g. degradation of toxic
pollutants, to the site where the specific
function is needed. However, applying a
single strain has often proven ineffective.
Asst Prof Sze Chun Chau’s laboratory
(SBS, NTU) explores and exploits bacterial
interplay in order to achieve a more
sophisticated level of Bioaugmentation.
Interactions between various bacterial
species bring about differing outcomes. A
compatible combination of bacterial
species, with complementary and
synergistic metabolic capabilities, can result
in a potent co-culture suitable for handling
applications not possible with pure cultures.
One of the greatest advantage of bacterial
co-cultures over pure cultures is that cocultures
are often more resistant to
environmental disturbances and fluctuation,
and hence, more self-sustaining. This work
has benefitted our industry partners in the
Environmental Biotechnology sector, e.g.
an air-purification device for removing
Volatile Organic Compound (VOC) will be
making use of the bacterial co-culture
formulated by Asst Prof Sze’s laboratory,
which can remove VOC more than 400%
faster, compared to their original version.
Licensing terms are being negotiated
currently.
11

Polarity exploration
The laboratory of A/Prof Jaume Torres (SBS,
NTU) developed together with Aquaporin A/S
(Denmark) a method to create giant protein vesicles
(GPVs). Fluorescence microscopy is used to
characterize GPV morphology and protein–lipid
hydrophobic interactions. Specifically, they
employed generalized polarization imaging to
monitor the polarity around the protein
transmembrane region of aquaporins labeled with the
polarity-sensitive probe Badan.
Their recently published work (1,2), describes how
giant protein vesicles (GPVs) of ≥10 μm can be
created by solvent-driven fusion of large vesicles
(0.1-0.2 μm) with reconstituted membrane proteins.
The researchers found that formation of GPVs
proceeded from rotational mixing of proteinreconstituted
large unilamellar vesicles (LUVs) with
a lipid-containing solvent phase. GPVs can be made
by using n-decane and squalene as solvents, and
applied generalized polarization (GP) imaging to
monitor the polarity around the protein
transmembrane region of aquaporins labeled with the
polarity-sensitive probe Badan. Specifically, they
created GPVs of spinach SoPIP2;1 and E. coli AqpZ
aquaporins. There findings show that hydrophobic
interactions within the bilayer of formed GPVs are
influenced not only by the solvent partitioning
propensity, but also by lipid composition and
membrane protein isoform.
1. Hansen, J. S., Vararattanavech, A., Plascencia, I., Greisen, P. J., Bomholt, J. Torres, J. Emneus, J., Helix-Nielsen, C.
(2011) Interaction between sodium dodecyl sulfate and membrane reconstituted aquaporins: a comparative study of
spinach SoPIP2;1 and E. coli AqpZ (2011) BBA –Biomembranes, 1808, 2600-2607.
2. Jesper S. Hansen, A. Vararattanavech, T. Vissing, J. Torres, J. Emnéus, C.H. Nielsen (2011) Formation of giant protein
vesicles by a lipid cosolvent method. ChemBioChem 12, 2856-2862.
12

Insights into RNA unwinding and
ATP hydrolysis by the flavivirus NS3 protein
Together with the NS5 polymerase, the
NS3 helicase has a pivotal function in
flavivirus RNA replication and constitutes an
important drug target. The laboratory of
A/Prof Julien Lescar (SBS, NTU) and the
Novartis Institute for Tropical Diseases
(Singapore) captured the dengue virus NS3
helicase at several stages along the catalytic
pathway including the forms bound to
single-stranded (ss) RNA, to an ATP
analogue, to a transition-state analogue and
to ATP hydrolysis products. RNA
recognition appears largely sequence
independent in a way remarkably similar to
eukaryotic DEAD box proteins Vasa and
eIF4AIII. On ssRNA binding, the NS3
enzyme switches to a catalytic- competent
state imparted by an inward movement of the
P-loop, interdomain closure and a change in
the divalent metal coordination shell,
providing a structural basis for RNAstimulated
ATP hydrolysis. These structures
demonstrate for the first time large
quaternary changes in the flaviviridae
helicase, identify the catalytic water
molecule and point to a β-hairpin that
protrudes from subdomain 2, as a critical
element for dsRNA unwinding. They also
suggest how NS3 could exert an effect as an
RNA-ancho ring device and thus participate
both in flavivirus RNA replication and
assembly.
1. Luo, D., Xu, T., Watson, R. P., Scherer-Becker, D., Sampath, A., Jahnke, W., Yeong, S. S., Wang, C. H., Lim, S. P., Strongin,
A.,Vasudevan, S. G., Lescar, J. (2008) EMBO J. 27, 3209–3219
13

Functional analysis of two cavities
in flavivirus NS5 polymerase
Flavivirus NS5 protein encodes
methyltransferase and RNA-dependent RNA
polymerase (RdRp) activities. Structural analysis
of flavivirus RdRp domains uncovered two
conserved cavities (A and B). Both cavities are
located in the thumb subdomains and represent
potential targets for development of allosteric
inhibitors. The laboratory of A/Prof Susana
Geifman Shochat (SBS, NTU) analyzed in
collaboration with the Novartis Institute for
Tropical Diseases (Singapore) the function of
the two RdRp cavities. Amino acids from both
cavities were subjected to mutagenesis analysis
in the context of genome-length RNA and
recombinant NS5 protein; residues critical for
viral replication were subjected to revertant
analysis. For cavity A, they found that only one
(Lys-756) of the seven selected amino acids is
critical for viral replication. Alanine substitution
of Lys-756 did not affect the RdRp activity,
suggesting that this residue functions through a
nonenzymatic mechanism. For cavity B, all four
selected amino acids (Leu-328, Lys-330, Trp-
859, and Ile-863) are critical for viral
replication. Biochemical and revertant analyses
showed that three of the four mutated residues
(Leu-328, Trp-859, and Ile-863) function at the
step of initiation of RNA synthesis, whereas the
fourth residue (Lys-330) functions by interacting
with the viral NS3 helicase domain. Collectively,
their results have provided direct evidence for
the hypothesis that cavity B, but not cavity A,
from dengue virus NS5 polymerase could be a
target for rational drug design.
1. Zou G., Chen Y. L., Dong H., Lim C. C., Yap L. J., Yau Y. H., Shochat S. G., Lescar J., Shi P. Y. (2011) J. Biol. Chem. 286,
14362-14372. (2011) J. Biol. Chem. 286, 14362-14372
14

Important Role for Heat Shock Protein 90
in Virus Particle Assembly
The laboratory of A/Prof Richard
Sugrue (SBS, NTU) and researchers of
JEOL U.S.A. Inc., (Massachusetts)
identified the presence of virus-associated
cellular proteins that may play a role in
respiratory syncytial virus (RSV)
maturation. Fluorescence microscopy of
virus-infected cells revealed the presence
of virus-induced cytoplasmic inclusion
bodies and mature virus particles, the
latter appearing as virus filaments. In situ
electron tomography suggested that the
virus filaments were complex structures
that were able to package multiple copies
of the virus genome. The virus particles
were purified, and the protein content was
analyzed by one-dimensional nano-LC
MS/MS. In addition to all the major virus
structural proteins, 25 cellular proteins
were also detected, including proteins
associated with the cortical actin network,
energy pathways, and heat shock proteins
(HSP70, HSC70, and HSP90).
Immunofluorescence microscopy of infected cells stained with antibodies against
relevant virus and cellular proteins confirmed the presence of these cellular proteins in
the virus filaments and inclusion bodies. The relevance of HSP90 to virus infection
was examined using the specific inhibitors 17-N-Allylamino-17demethoxygeldanamycin.
Although virus protein expression was largely unaffected by
these drugs, we noted that the formation of virus particles was inhibited, and virus
transmission was impaired, suggesting an important role for HSP90 in virus
maturation. This study highlights the utility of proteomics in facilitating both our
understanding of the role that cellular proteins play during RSV maturation and, by
extrapolation, the identification of new potential targets for antiviral therapy.
1. Radhakrishnan, A., Yeo, D., Brown, G., Myaing, M. Z., Iyer, L. R., Fleck, R., Tan, B.-H., Aitken, J., Sanmun, D., Tang, K.,
Yarwood, A., Brink, J., Sugrue, R. J. (2010) Molecular & Cellular Proteomics 9:1829–1848
15

Small Molecule Inhibitors That
Selectively Block Dengue
Crystal structure analysis of Flavivirus
methyltransferases uncovered a
flavivirus-conserved cavity located next
to the binding site for its cofactor, Sadenosyl-methionine
(SAM). Chemical
derivatization of S-adenosylhomocysteine
(SAH), the product
inhibitor of the methylation reaction, with
substituents that extend into the identified
cavity, generated in- hibitors that showed
improved and selective activity against
dengue virus methyltransferase (MTase),
but not related human enzymes. The
crystal structure of dengue virus MTase
with a bound SAH derivative, solved by
the laboratory of A/Prof Julien Lescar
(SBS, NTU) and the Novartis Institute
for Tropical Diseases (Singapore),
revealed that its N6-substituent bound in
this cavity and induced conformation
changes in residues lining the pocket.
These findings demonstrate that one of
the major hurdles for the development of
methyltransferase-based therapeutics,
namely selectivity for disease-related
methyl- transferases, can be overcome.
1. Lim, S. P., Sonntag, L. S., Noble, C., Nilar, S. H., Ng, R. H., Zou, G., Monaghan, P., Chung, K. Y., Dong, H., Liu, B.,
Bodenreider, C., Lee, G., Ding, M., Chan, W. L., Wang, G., Jian, Y. L., Chao, A. T, Lescar, J., Yin, Z., Vedananda, T. R.
Keller, T. H., Shi, P.Y. (2011) J. Biol.Chem. 286, 6233–6240
16

a novel mechanism of inhibition
of the TB drug TMC207
With one-third of mankind infected
subclinically, and an incidence of nine
million new cases of active tuberculosis
disease (TB) and two million deaths per
year, Mycobacterium tuberculosis
remains the most important bacterial
pathogens in the world. TMC207 was
identified in a phenotypic whole cell
screen and described to interfere with the
M. tuberculosis F-ATP synthase.
Using NMR-, SAXS, fluorescence
spectroscopy and mutagenesis, the
laboratory of Prof Gerhard Grüber
(SBS, NTU) in collaboration with the
Novartis Institute for Tropical Diseases
(Singapore) demonstrated that the new
TB drug candidate TMC207, proposed to
bind to the proton translocating c-ring,
also bind to the coupling subunit ε of the
M. tuberculosis F-ATP synthase. The data
demonstrate that TMC207 forms a wedge
between the two rotating subunits c and ε
by interacting with the residues W15 and
F50 of ε and the c-ring, respectively. T19
and R37 of ε provide the necessary polar
interactions with the drug molecule. This
new mechanism of TMC207 binding
provides the basis for the design of
antimycobacterials, targeting the F-ATP
synthase in M. tuberculosis.
1. Biuković, G., Basak, S., Manimekalai, M. S. S., Rishikesan, S., Roessle, M, Dick, T., Rao, S. P. S, Grüber, G. (2012)
Variations of subunit � of the Mycobacterium tuberculosis F-ATPsynthase and a novel mechanism of inhibition of the
TB drug TMC207. PNAS
17

Bactericidal Boomerangs
Lipopolysaccharide (LPS), a major
component of the outer membrane of
Gram-negative bacteria, is perhaps best
recognized as a potent inducer of the
innate immune system. However, LPS
also acts as a barrier to exogenous
compounds and a chaperone to aid in the
folding of outer membrane proteins.
Therefore, molecular interactions with
LPS should be considered when
designing antimicrobial drugs. Dr. Surajit
Bhattacharjya and colleagues (SBS,
NTU) do just that, describing structure
activity correlations for a series of 12residue
peptides (based on chemokines
and neutrophil bactericides) in LPS. They
observed that long range aromaticaromatic
packing between residues
located at positions 4 and 9 (forming a
boomerang-like conformation) was
crucial for both neutralizing LPS and
antimicrobial activity; the ability of these
active peptides to neutralize LPS
appeared to correlate with their ability to
perturb LPS micelles. This atomic level
knowledge should be useful in providing
the building blocks for designing novel
peptides for bacterial outer membranes.
1. Bhunia, A., Mohanram, H., Domadia, P. N., Torres, J., Bhattacharjya, S. (2009) Designed beta-boomerang antiendotoxic and
antimicrobial peptides:structures and activities in lipopolysaccharide. J. Biol. Chem. 284, 21991-22004
18