9th Iran Biophysical Chemistry Conference, 24-25 February 2010, Tarbiat Modares University, Tehran, Iran
were investigated using spectrophotometry ABTS-based method (reduction
of
the
cation
ethylenebenzothiazoline-6-sulfonic
radical
of
acid)).The
2,20-azinobis(3-
results
indicate
the
1- Department of Biology, College of Sciences, Shiraz University, 71454, Shiraz, Iran, 2- Biopolymères Interactions Assemblages, INRA, équipe Fonctions et Interactions des Protéines Laitières, B.P. 71627,
overall antioxidant activity of camel caseins and their hydrolysis were
44316 Nantes Cedex 3, France, 3- Institute of Biochemistry and
higher than bovine caseins and peptide fraction between 5-10 kDa
Biophysics (IBB), University of Tehran, Tehran, Iran.
showed the highest antioxidant activity. It can be concluded that camel caseins or their hydrolysates can be used as a novel ingredient for
Beta-CN (ǃ-CN) molecule is a single chain protein of known sequence
producing nutraceuticals and natural drugs with high antioxidant
containing a cluster of five phosphoseryl residues in the N-terminal
activity.
hydrophilic domain. This protein is one of the highly allergenic components of cow's milk which possesses multiple sequential
Key words: antioxidant peptides, free-radicals, Camel Casin, kinetic
antigenic determinants (epitopes) in its primary structure. Moreover ǃ-
parameters.
CN is member of intrinsically unstructured protein (IUP) family
Abstract No.72
and purified from E. coli, ǃ-CN lacks the phosphoryl residues, because
exhibiting chaperone-like activity in vitro. In this study as expressed the prokaryotic host does not realize post-translational phosphorylation The biophysical chemistry interaction of silver nanoparticles
of the eukaryotic protein (ǃ-CN). Subsequently, the impact of
and doxorubicin
phosphoryl residues on IgE mediated immune reactivity (allergenicity) and chaperoning function were investigated and compared using the
Azadeh Hekmat1, Ali Akbar Saboury1 and Adeleh Divsalar1,2 1- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran, 2- Department of Biological Sciences, Tarbiat Moallem University, Tehran, Iran
beings, occurs when abnormal cells grow out of control in one or both breasts. Anthracyclines, particularly doxorubicin (DOX) are widely used antibiotics for medical treatments of breast cancer. In this research, we have studied the interaction between silver nanoparticles and drug
of
doxorubicin
using
UV-visible
enzyme-linked immunosorbant assay (ELISA) were performed in order to compare chaperoning abilities and allergenicity of the beta-caseins respectively. The results exhibit major roles played by the cluster of phosphoseryl residues in both chaperoning activity and in shaping of
Breast cancer, which affects an important percentage of human
anticancer
recombinant and native ǃ-CNs. Spectroscopic measurement and
spectroscopy,
fluorescence spectroscopy and circular dichruism (CD) at 37 ˚C. We have determined the binding constant (Ka=215.34 mM-1) and
the allergenicity profile of ǃ-CN. Consequently this study suggests the major phosphorylation site as one of the important antigenic determinant elements along the primary structure of beta-casein. Moreover phosphoseryl cluster plays significant role in amphipathic character and subsequently chaperoning function of this molecule. Key
words:
Beta-casein,
Chaperone-like
activity,
Allergenicity,
Phosphoseryl cluster.
enthalpies of this interaction. The interaction of doxorubicin with varying silver nanoparticle concentration represented one binding sites. Altogether, our data indicated that there is a strong interaction between silver nanoparticles and DOX. Key
words:
Doxorubicin,
Silver
Abstract No.74 Molecular dynamics study of transition conformation in
nanoparticles,
Thermodynamic
Human serum albumin denaturation
parameters.
Farideh Zergani 1, Mohammad-Reza Dayer2 and Omid Ghayour3
Abstract No.73
1- Department of Chemistry, Science and Research Branch of Islamic Azad University of Ahvaz, 2- Department of Biology, Faculty of
Impact of the Major Phosphorylation Site on Chaperoning Function and Allergenicity of Beta-Casein
Science, Shahid Chamran University, 3- Department of D3, Yapna TeX, Yekta Pouya Company
Reza Yousefi*1, Hojjat Khalili-Hezarjaribi1, Zohreh Tavaf Langeroudi1,
Human serum albumin (HSA) is most abundant protein in human blood
Hajar Zamani1, Thomas Haertle2, Ali-Akbar Moosavi-Movahedi3
plasma, is produced in the liver and comprises about half of the blood serum protein. HSA is soluble in serum and is important in regulating
S32
Journal of the Iranian Chemical Society, Vol. 7, Suppl. 1, February 2010
blood osmotic pressure. HSA serves as carriers for molecules with low
Molecular chaperones form a family of proteins believed to evolve
water solubility, including hydrophobic hormones, unconjugated
towards prevention of protein unfolding and aggregation in denaturing
bilirubin, free fatty acids, calcium ions, and some exogenous chemicals
conditions. Consequently, chaperones play important role in preventing
such as drugs. In the present work, we used molecular dynamics
of the serious problems so called aggregation diseases such as
simulation methods to study the structural alterations and nature of
Alzheimer’s, Parkinson’s, and Huntington’s, Creutzfeldt - Jakob disease,
forces involved in the transition from native to denatured states of
cataract and type II diabetes. In this study the ability of bovine beta-
HSA. Gromacs version 3.3.3. package installed over UBUNTU Linux
casein to prevent aggregation of pancreatic insulin was considered as a
version 8.10 (Intrepid) on a Intel ® Pentium ® M based PC at 1.6
sign of its chaperone-like activity. The chemical-induced aggregation of
GHz with 469.5 MiB of Ram package, and ffgmx force field was
insulin was detected by measuring of the increase in optical density at
used in the present work. The coordinates used for HSA was
360 nm as a function of time. For quantitative estimation of
obtained from RCSB Protein Data Bank, with PDB ID: 3CX9. The
chaperone-like activity of beta-casein, k1 and Alim were derived from
protein was equilibrated in a cubic box with 9.581nm x 5.959nm x
the aggregation curves, with the assumption that, as proposed
9.717nm dimensions. Energy minimization was carried out using
already, aggregation follows completely first order kinetics. Alim is the
steep integrator and Fmax were chosen 1000 for 1000 step.
limiting value of absorbance (A) at tĺ and k1 is the rate constant of
Molecular dynamics with all-bond constrain for 200ps and finally
the first order reaction. The k1.Alim product is the initial rate of
no constrain were used to simulate done for up to 4ns. Our results
aggregation and it is expressed in unit of absorbency per time unit. To
show heating up the albumin solution exerts vast alterations in the
quantify chaperone-like activity of beta-casein at different molar ratios
system leading to denaturation of albumin. Stepwise refinement of
of chaperone/target protein, k1.Alim of each experiment was divided
simulation trajectories revel cooperative events during denaturation.
individually per (k1.Alim)0 of the control experiment (absence of beta-
Increase in kinetic energy at 52qC leads to decrease in solvent-protein
casein) and subtracted from unit. The resulting values varied from zero
H. Bond cause a simultaneous increase in protein-protein H. Bond.
(in the absence of casein chaperone) to one (where k1.Alim= 0). These
However obvious decrease in gyration radius and in solvent accessible
values,
surface area (SAS) proves the formation of a more compacted
chaperone/substrate ratio, are correlated directly with the chaperone-
conformation in albumin before denaturation takes place. More
like activities of beta-casein chaperone. The percentage of chaperone-
increasing in temperature causing H. Bond breakdown, converting
like activities can be obtained by multiplying the obtained values by
regular structures to random ones, and finally leading to completely
100. Advantage of the current approach is to apply combination of key
denatured structures, in about 70qC (Tm). We also studied the position
parameters (k1 and Alim) in measuring of chaperone-like activity.
increasing
from
0
to
1
with
the
increase
of
the
changing of Tryptophan-212 during the simulation. Trp(212) is known to lie in the hydrophobic pocket of HSA and is located on the surface of
Key words: Chaperone-like activity, Quantification, First order rate
sub domain 4 in domain II. Outgoing of Trp(212) at the melting
constant (k1), Limiting value of absorbance (Alim).
temperature is in accordance with denatured conformation. Key words: Molecular dynamics, HSA, gyration radius, hydrophobic
Abstract No.76
pocket, denaturation. The Importance of a Flexible Loop in Kinetic Pathway of Refolding of Iranian Firefly Luciferase Abstract No.75
and Its Thermodynamic Stability
A Novel Approach to Quantify the Chaperone-Like activity 1
1*
Khosrow Khalifeh, Bijan Ranjbar*, Bagher Said Alipour, Saman Hosseinkhani*
1
Reza Yousefi , Hajar Zamani , Zohreh Tavaf Langeroudi , Marziyeh Valifard1, Hojjat Khalili- Hezarjaribi1, Thomas Haertle2, Ali-Akbar Moosavi-Movahedi3
Department of Biophysics & Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, P.O. Box, 14115–175 Tehran,
1- Department of Biology, College of Sciences, Shiraz University,
Iran, E-mail:
[email protected],
[email protected]
71454, Shiraz, Iran, 2- Biopolymères Interactions Assemblages, INRA, équipe Fonctions et Interactions des Protéines Laitières, B.P. 71627,
In order to elucidate the effect of a flexible ǃ-strands connecting loop
44316 Nantes Cedex 3, France, 3- Institute of Biochemistry and
on the stability of folded state and kinetic pathway of refolding of
Biophysics (IBB), University of Tehran, Tehran, Iran.
Iranian
firefly
luciferase
(Lampyris
turkestanicus), kinetics and
S33
