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Center For Protein Structure And Function |
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| Overview |
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 Genome
sequences are not sufficient to provide
an understanding of how living systems
work, because the DNA sequences must be
expressed as proteins, which fold into
their specific three-dimensional structures
that determine how they function. Some
proteins may also be chemically modified
after synthesis or be converted from inactive
to active forms. In addition, different
proteins may be synthesized in different
tissues or at different stages of development.
Thus understanding of living processes
requires understanding of structure and
function relationships in proteins.
For this reason, the "Center for
Protein Structure and Function (CPSF)"
was founded as a Center for Excellence
of the Faculty of Science, Mahidol University
2001, to serve as an interdisciplinary
research laboratory for elucidating the
molecular basis of protein action. CPSF
consists of 6 staff members from three
departments of the faculty, headed by
Professor M.R. Jisnuson Svasti. It is
well equipped with modern equipment provided
by the faculty, including X-ray crystallography
and stop-flow enzyme kinetics and is linked
with the Laboratory of Biochemistry at
the Chulabhorn Research Institute, which
has facilities for protein sequencing
and proteomics. |
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| Networking |
| Staff
members of CPSF have extensive research networks
both locally and overseas. In Thailand, there
is extensive research collaboration with staff
from: a) various departments and institutes at
Mahidol University; b) other universities, such
as Kasetsart University, Suranaree University
of Technology, Khon Kaen University, Prince of
Songkhla University, Srinakarintwirot Prasarnmitr
University, Naresuan University, Mahasarakham
University, Mae Fah Luang University; c) various
research institutions, such as the National Center
for Genetic Engineering and Biotechnology (BIOTEC)
and the Chulabhorn Research Institute. Overseas,
CPSF staff also collaborate with laboratories
in U.S.A., Canada, Belgium, Italy, Sweden and
Taiwan. In 2006, a Protein Society of Thailand
was founded to link protein scientists throughout
Thailand: this society has attracted much interest,
and its annual meetings are attended by some 400
staff and students. |
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| Research |
| CPSF
has six major research areas, funded by various
agencies such as the Thailand Research Fund, BIOTEC,
and Mahidol University. These are: |
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Plant glycosidase
enzymes |
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Glycosidase
enzymes hydrolyze carbohydrate compounds, such
as oligosaccharides and glycosides, which can
function in cellular recognition, or act as components
of drugs, flavors and scents. The beta-glucosidases
are interesting as models for studying structure
and function relationships, since they catalyze
similar reactions, but show different catalytic
properties. Novel enzyme and substrate combinations
have been isolated from Thai plants. The special
properties of certain enzymes are being used to
develop enzymatic methods for synthesis of glycosides
and oligosaccharides. The three-dimensional structures
of bacterial chitinase, rice beta-glucosidase,
and cassava linamarase are being determined by
X-ray crystallography. |
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Drug targets in malaria |
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A potential strategy
for treatment of malaria is to inhibit enzymes
required by malarial parasites, that are absent
from the human host. The three-dimensional structures
of P. falciparum dihydrofolate reductase-thymidylate
synthetase complex and P. vivax dihydrofolate
reductase, involved in pyrimidine biosynthesis,
have been determined in collaboration with researchers
at BIOTEC. This not only improves understanding
of the structural basis of drug resistance, but
also assists in the design of anti-malarial drugs.
Another target enzyme is parasite plasmepsin,
which degrades hemoglobin in the red blood cell,
where understanding of three-dimensional structure
will also be important for design of specific
inhibitors. Mechanistic studies are also being
performed on serine hydroxymethyltransferase (SHMT),
a PLP-dependent enzyme, which plays an indispensable
role in nucleic acid biosynthesis in malarial
parasites, so specific inhibitors of this enzyme
also have potential as anti-malarial drugs. |
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Enzymes in the synthesis
of penicillin derivatives |
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Antibiotics
in the penicillin group are being imported at
considerable cost. Work on enzymes, involved in
the synthesis of penicillin derivatives, have
potential applications in developing synthetic
processes locally. One enzyme, D-phenylglycine
aminotransferase, which catalyzes an unusual stereo-inversion
reaction project, has been crystallized, and its
three-dimensional structure is being determined
to elucidate the reaction mechanism. Another project
attempts to modify the specificity of the enzyme
penicillin G acylase from B. megaterium by protein
engineering, to generate a novel enzyme cephalosporin
acylase for synthesis of cephalosporin antibiotics. |
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Mechanistic studies of
flavoprotein oxygenase enzymes |
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These oxygenases have
flavin as coenzymes and catalyze the addition
of oxygen or hydroxyl groups to substrates producing
more soluble or readily degradable compounds.
Of special interest are the oxygenases acting
on aromatic compounds, since they may be useful
for bioremediation of aromatic waste. The thermodynamic
and catalytic properties of several enzymes are
being studied, including 2-methyl-3-hydroxypyridine-5-carboxylic
acid oxygenase and p-hydroxyphenylacetate hydroxylase.
Recent studies involve a luciferase-flavin reductase
system, which causes light emission in bacteria,
and has potential application for the development
of biosensors. |
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Sericin-specific proteinase
enzyme |
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Silk
fibres from Bombyx mori silkworms consist of a
major fibrous protein fibroin and other minor
proteins called sericin, which cover the fibroin
fiber with sticky layers to form the cocoon. Degumming
of sericin is necessary for preparation of soft,
shiny, and whitened silk ready for dying, but
traditional practice, using alkaline solutions
and high temperatures, is difficult to control.
A search is being made for proteinase(s) from
microorganisms, which digest sericin without degrading
fibroin, which will allow milder enzymatic degumming. |
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| Awards |
| The
results of research at CPSF have been published
in journals with high impact factors. In addition,
CPSF staff members have won numerous awards at
national level, namely: Outstanding Scientist
of Thailand Award, Distinguished Researcher Award,
Outstanding Lecturer Award of Thailand, 3 Young
Scientist Awards, UNESCO-L’Oreal Fellowship,
and Mahidol University Prize for Research. |
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| Selected Publications |
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| 1. |
Siripurkpong, P., Yuvaniyama, J.et
al. (2002) Active Site Contribution to Specificity
of the Aspartate Proteases Plasmepsins I and II.
J Biol Chem 277, 41009-13. |
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| 2. |
Yuvaniyama, J., et al. (2003) Insights
into Antifolate Resistance from Malarial DHFR-TS
Structures. Nature Struct Biol 10 (5), 357–65. |
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| 3. |
Srisomsap, C., et al. (2004) Proteomic
Analysis of Cholangiocarcinoma Cell Line. Proteomics
4, 1135-1144. |
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| 4. |
P. Kongsaeree, et al. Crystal structure
of dihydrofolate reductase from Plasmodium vivax:
Pyrimethamine Displacement Linked with Mutation-induced
Resistance. Proc Natl Acad Sci USA (2005), 102,
13046-51. |
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| 5. |
Sucharitakul, J., Chaiyen, P.,
et al. (2006) Kinetic Mechanisms of the Oxygenase
from a Two-component Enzyme, p-Hydroxyphenyl Acetate
3-Hydroxylase from Acinetobacter baumannii. J
Biol Chem 281(25), 17044-53. |
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| 6. |
Alfieri, A. et al. (2007) Structure
of the Monooxygenase Component of a Two-component
Flavoprotein monooxygenase Proc. Natl. Acad. Sci.
U.S.A. 104, 1177-1182. |
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| 7. |
Hommalai, G., Withers, S.G., Chuenchor,
W., Cairns, J.R.K and Svasti, J. (2007) Enzymatic
synthesis of cello-oligosaccharides by rice BGlu1
beta-glucosidase glycosynthase mutants. Glycobiology
2007, Apr 3; [Epub ahead of print] |
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| For further information,
contact: scjsv@mahidol.ac.th
or scjyv@mahidol.ac.th |
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