Anđelković, Uroš

Fonovic, M.

Lah, Jurij

Pajic, I.

Prislan, I.

Sladić, Dušan

Tufegdžić, Srđan

Turk, B.

Vidmar, R.

Vizovisek, M.

FEBS Journal

English

 CER - Central Repository of the Institute of Chemistry;  Technology and Metallurgy

synthase with Q211E substitution. Using the crystal violet stain-
ing assay, we found that susceptibility of the cells transfected
with either vector was ten times higher than susceptibility of the
untransfected cells. In the thin layer chromatography overlay of
glycolipids derived from transfected 2102Ep cells, Shiga toxins
were found to bind only to Gb3. TLC overlay of glycolipids
from red blood cells also revealed the binding to Gb3, but in
NOR-positive erythrocytes an additional band was detected,
migrating similarly to P1 glycolipid. Thus, our results show that
Shiga toxins VT1 and VT2 do not bind to NOR antigens sug-
gesting that the penultimate galactose residue of the Shiga toxin
receptor cannot be replaced by N-acetylgalactosamine.
SW06.S28–18
X-ray structure of a stable protease-resistant
glectin-9 with short linker
H. Yoshida, N. Nishi, M. Teraoka, S. Yamashita and
S. Kamitori
Life Science Research Center, Kagawa University, Kagawa, Japan
Human Galectin-9 (hG9) belongs to a lectin family and has two
different carbohydrate recognition domains (N-terminal and C-
terminal CRDs) which are specific to beta-galactosides. The
physiological function of hG9 is miscellaneous and known to be
an eosinophil chemoattractant, T-cell immunoglobulin domain
and mucin domain 3 ligand, and inducer of T helper 1 cell apop-
tosis. There are isoforms depending on the length of the linker
region between N- and C- CRDs. Two isoforms, hG9L (355 a.a.)
and hG9M (323 a.a.), are protease sensitive due to their long lin-
ker with ca. 30–60 a.a. To date, hG9Null has been known as
protease resistant hG9 mutant with short linker (2 a.a.) and
retaining the biological function of native hG9, eosinophil
chemoattractant activity, apoptosis induction of activated T-cells
and pleiotropic immune response [1]. The structure of each
CRDs has been already available, however the whole structure of
hG9 with two CRDs is not reported and is intriguing for under-
standing of interaction of N- and C- CRDs. In this study, we
determined the crystal structure of a stable hG9Null with a muta-
tion of sugar binding site of C-CRD. Each CRD structure has
no big difference with the previously reported structure as known
as beta sandwich structure. Although the linker region including
N-terminal region of C-CRD (10 a.a.) was not visible in the elec-
tron density maps, N- and C- CRD interact with each other via
a metal ion, making a rigid stable structure of hG9Null mutant.
Recently, Nishi et al. constructed a highly soluble and stable
hG9 mutant with a truncated and optimized linker region (284
a.a.) [2]. Interestingly, the optimized truncated linker region cor-
responds to the invisible linker region in our crystal structure of
hG9Null mutant. It is still unknown that N- and C- CRD of
hG9 can interact with each other without depending on the
length of linker region. Although it might be occasional, our
crystal structure of hG9Null mutant showed the possibility of
their interaction.
Reference
1. Nishi, N. et al., FEBS Letters. 579, 2058–2064 (2005).
2. Itoh, A. et al., Glycobiology. in press.
SW06.S28–19
A new lectin from coral Gerardia savaglia:
purification, physico-chemical characterization
and thermodynamics of saccharide binding
U. Andjelkovic1, I. Pajic1, M. Vizovisek2, R. Vidmar2, I. Prislan3,
S. Tufegdzic1, M. Fonovic2,4, J. Lah3, B. Turk2,4 and D. Sladic5
1Department of Chemistry, Institute for Chemistry, Technology
and Metallurgy, University of Belgrade, Belgrade, Serbia,
2Department of Biochemistry, Molecular and Structural Biology,
Jozef Stefan Institute, Ljubljana, Slovenia, 3Department of
Physical Chemistry, Faculty of Chemistry and Chemical
Technology, University of Ljubljana, Ljubljana, Slovenia, 4Centre
of Excellence for Integrated Approaches in Chemistry and Biology
of Proteins, Ljubljana, Slovenia, 5Department of Organic
Chemistry, Faculty of Chemistry, University of Belgrade, Belgrade,
Serbia
A new lectin has been purified from Mediterranean coral G. sava-
glia by affinity chromatography on mannose-sepharose. Two-
dimension electrophoresis showed a single spot at pI 8.9, while
MALDI TOF/TOF mass spectrometry analysis revealed four
molecular variations with molecular weights 16 803, 16 769,
16 617 and 16 583 Da. Identical N-terminal amino acid sequence
confirmed similarity between these four molecules. The hemag-
glutination activity of the lectin was analyzed at different temper-
atures, pH and in the presence of divalent cations. Far UV
circular dichroism (CD) showed unusual spectra with high con-
tent of b-structures. Thermal stability was investigated by differ-
ential scanning calorimetry (DSC) and CD spectroscopy. The
DSC yielded a curve with endothermic peak above 72°C with
midpoint at 78.9°C, accompanied with loss of structure con-
firmed by CD. Both methods showed that the thermal unfolding
process is irreversible. Lectin-D-mannose interactions were stud-
ied by CD and isothermal titration calorimetry (ITC). No
changes in far UV CD spectra have been observed upon addition
of mannose even in the presence of divalent cations. On the other
hand ITC studies showed binding of mannose is accompanied by
large negative enthalpy change (due to high number of hydrogen
bonds) and unfavorable entropy contribution (due to solvent
rearrangement or loss of ligand conformational flexibility).
Obtained affinity for D-mannose is in millimolar range, which is
in accordance with results reported previously for specific lectin –
saccharide interactions.
Biological functions of lectins in corals are poorly understood.
There are suggestions that they are important for symbiosis with
algae and pathogen defense. Corals are endangered species and
one of the reasons for their extinction is connected with the loss
of symbiosis with algae. This study presents a novel type of lectin
with unusual mannose specific structure and provides basis for
understanding role of lectins in coral.
SW06.S28–20
Effects of astragalus, lemon balm, clove,
fenugreek and cinnamon on blood glucose
level after oral glucose loading in rats
B. Ozturk1, H. Serdar Ozturk2 and I. Durak2
1Selcuk University Faculty of Medicine, Department of Medical
Biochemistry, Konya, Turkey, 2Ankara University Faculty of
Medicine, Department of Medical Biochemistry, Ankara, Turkey
Background and aim: Herbs like astragalus, lemon balm, clove,
fenugreek and cinnamon are consumed in various ways (dietary
supplement, herbal tea etc.) all over the world. Consumption of
these herbs (along with other health beneficial effects) has been
mentioned to be helpful in decreasing blood glucose levels of dia-
FEBS Journal 280 (Suppl. 1) (2013) 3–617
ª 2013 The Authors. FEBS Journal ª 2013 FEBS 531
SW06 General Aspects of Biochemistry Abstracts


A new lectin from coral Gerardia savaglia: purification, physico-chemical characterization and thermodynamics of saccharide binding

http://cer.ihtm.bg.ac.rs/bitstream/id/14635/2013-FEBS_Journal 529.pdf

A new lectin from coral Gerardia savaglia: purification, physico-chemical characterization and thermodynamics of saccharide binding

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