Protein & Peptide Letters, Volume 10, No. 3, 2003
Antimicrobial
Peptides from Anurans Skin Secretions Pp.227-238
Anna
Christina C. Nascimento , Wagner Fontes , Antonio Sebben and Mariana S. Castro
Polymeric
Aspects of Protein Folding: a Brief Overview Pp.239-245
Olga
Tcherkasskaya and Vladimir N. Uversky
Cytochrome
C Is a Hydrogen Peroxide Scavenger In Mitochondria Pp.247-253
Zhi-Bo
Wang, Min Li, Yungang Zhao and Jian-Xing Xu
Site-Directed
Mutagenesis and Preliminary X-Ray Crystallographic Studies of the Tabtoxin
Resistance Protein
Pp.255-263
Yi
Ding, Shentao Li, Xiaofeng Li, Fei Sun, Jinyuan Liu, Nanming Zhao and Zihe Rao
Oxidation
of Goat Hepatic Galectin-1 Induces Change in Secondary Structure Pp.265-275
Abhay
H. Pande , Rajesh K. Gupta, Sumati and Krishnan Hajela
A
Simple Parameter Relating Sequences with Folding Rates of Small a Helical Proteins
Pp.277-280
Hui
Shao, Yi Peng and Zong-Hao Zeng
Recombinant
Expression, Purification and Characterisation of The Hmg Domain of Human Sry Pp.281-286
Sabine
Kelly , Julia Yotis , Mary Macris , Vincent Harley
Isolation
And Characterization of a new Dgalactose- Binding Lectin from Sambucus Racemosa
L. Pp.287-293
M.
Angeles Rojo , Lucia Citores , Pilar Jimenez , J. Miguel Ferreras , F. Javier
Arias , Enrique Mendez and Tomas Girbes
Molecular
Modeling of the Neurohypophyseal Receptor/Atosiban Complexes Pp.295-302
Magdalena
J. Slusarz, Rafal_ Slusarz, Rajmund Kazmierkiewicz Jerzy Trojnar , Kazimierz
Wisniewski and Jerzy Ciarkowski
Fused
Rola Protein Enhances b-Glucoronidase Activity 50-Fold: Implication for Rola
Mechanism of Action
Pp.303-311
Leila
Maria G. Barros , Rosane H. Curtis ,
Antônio Américo B. Viana , Laura Campos
and Mauro Carneiro
Monitoring
Bone Loss Using Elisa and Surface Plasmon Resonance (Spr) Technology Pp.313-319
Feng-Di T. Lung , Huey-Yi Chen and Hsing-Tzu Lin
Arrhenius
Analysis of the Electrophorus Electricus Acetylcholinesterase-Catalyzed
Hydrolysis of Acetylthiocholine
Pp.321-324
Jesse
Oakes, Tina Nguyen and B. Mark Britt
Purification
And Crystallization of A Lysr-Type Transcriptional Regulator Cbnr from
Ralstonia Eutropha Nh9
Pp.325-329
Shin Muraoka , Rumi Okumura , Yoshitaka Uragami , Takamasa Nonaka , Naoto Ogawa , Kiyotaka Miyashita and Toshiya Senda
[Back to top] Antimicrobial
Peptides from Anurans Skin Secretions
Anna
Christina C. Nascimento , Wagner Fontes , Antonio Sebben and Mariana S. Castro
This article is an
overview of antimicrobial peptides found in anurans skin secretions. These
molecules constitute an initial barrier against microbial infections because of
their activity against a large array of microorganisms. These peptides hold
remarkable pharmaceutical and technological interest since they selectively
kill microorganisms and are unlikely to induce resistance in pathogens. Also,
outstanding synergism occurs when these peptides are combined with classic
antibiotics and other antimicrobial peptides.
[Back to top]
Polymeric Aspects of
Protein Folding: A Brief Overview
Olga Tcherkasskayaa and Vladimir N. Uversky
Regardless of the
differences in primary amino acid sequences, protein molecules in a number of
conformational states behave as polymer homologues, allowing speculations as to
the volume interactions being a driving force in formation of equilibrium
structures. For instance, both native and molten globules exhibit key features
of polymer globules, where the fluctuations of the molecular density are
expected to be much less than the molecular density itself. Protein molecules
in the compact denatured (pre-molten globule) states possess properties of
squeezed coils. In fact, even high concentrations of strong denaturants (e.g.,
urea and GdmCl) more likely constitute bad solvents for protein chains. Thus,
globular proteins are probably never random coils without positional
correlations and biological polypeptide chains represent the macromolecular
coils below a critical point even under harsh denaturing conditions. Several
implications of these findings to protein folding are discussed.
[Back to top]
Cytochrome C Is a
Hydrogen Peroxide Scavenger in Mitochondria
Zhi-Bo
Wang, Min Li, Yungang Zhao and Jian-Xing Xu
The ability of
succinate–cytochrome c reductase (SCR) reduced cytochrome c to scavenge H2O2
was investigated. H2O2, whether added or produced by SCR,
was efficiently removed when cytochrome c was reduced by SCR. On the other
hand, ferrocytochrome c underwent re-oxidization when H2O2
was added. Thus, these results indicate that cytochrome c reduced by
succinate–cytochrome c reductase has the ability to regulate H2O2
in mitochondria.
[Back to top] Site-Directed Mutagenesis and Preliminary X-Ray
Crystallographic Studies of the Tabtoxin Resistance Protein
Yi
Ding, Shentao Li, Xiaofeng Li, Fei Sun, Jinyuan Liu, Nanming Zhao and Zihe Rao
Tabtoxin
resistance protein (TTR) is an enzyme that catalyzes the acetylation of
tabtoxin rendering tabtoxin-producing pathogens tolerant to their own
phytotoxins. According to the structure based detoxification mechanism of TTR,
three site-directed mutants Y141F, D130N and Y141F-D130N were constructed and
overexpressed in E. coli. The products were then purified and their properties
were analyzed by CD and DLS. Crystallization trials of two mutants Y141F
andY141F-D130N were preformed.
[Back to top] Oxidation of Goat Hepatic
Galectin-1 Induces Change in Secondary Structure
Abhay
H. Pande , Rajesh K. Gupta, Sumati and Krishnan Hajela
Galectin-1
requires a reducing environment for its lectin activity and the carbohydrate
binding function is destroyed in oxidizing condition. In this report we provide
direct evidence that the oxidation of goat hepatic galectin-1 perturbs its
carbohydrate recognition domain and this could be due to changes in secondary
structure of goat hepatic galectin-1. Conformational changes in goat hepatic
galectin-1 due to oxidation were investigated by absorption, fluorescence and
circular dichroism measurements.
[Back to top] A Simple Parameter Relating
Sequences with Folding Rates of Small a Helical Proteins
Hui
Shao, Yi Peng and Zong-Hao Zeng
It is found that
the helix parameter (HP), which favors clustering of non-polar residues, is
linearly correlated with the logarithms of rate constants of folding of small
two-state a-helical proteins. The definition is HP = NH
_1 S [fi+
(fi-1+fi+1)/2], where fi=1 or -1, if the i’th residue is hydrophobic or
hydrophilic, respectively, NH is the number of hydrophobic residues
and the summation is taken over the hydrophobic residues.
[Back to top] Recombinant Expression,
Purification and Characterisation of the Hmg Domain of Human Sry
Sabine
Kelly , Julia Yotis , Mary Macris , Vincent Harley
The HMG domain is
a DNA binding and bending ‘architectural’ motif involved in chromatin re-modelling
during transcription. Recombinant SRY HMG domain protein, 88 amino acids in
length, has been produced in E. coli. Using FPLC and a stirred ultra-filtration
cell, this domain has been purified to homogeneity and concentrated to yield
milligram quantities. Functional characterisation studies of the pure,
concentrated SRY HMG domain show the recombinantly expressed protein to be
active in terms of DNA binding and calmodulin binding activities.
[Back to top] Isolation and Characterization of
a new Dgalactose- Binding Lectin from Sambucus Racemosa L
M.
Angeles Rojo , Lucia Citores , Pilar Jimenez , J. Miguel Ferreras , F. Javier
Arias , Enrique Mendez and Tomas Girbes
A new acidic
lectin from red elder (Sambucus racemosa L.) bark has been isolated by affinity
chromatography and gel filtration. Noteworthy, and in contrast to other
Sambucus species, red elder bark lacks acidic non-toxic type 2
ribosome-inactivating proteins but has basic ribosome-inactivating protein activities.
The new lectin (SRLbm) shows specificity for N-Ac-Galactosamine/D-Galactose and
has an apparent Mr of 30,000. The N-terminal amino acid sequence displays a
close homology with other lectins and B chains of non-toxic type 2
ribosome-inactivating proteins nigrins and ebulins present in other Sambucus
species. SRLbm triggers red blood cell agglutination in the range 4-12 mg/ml.
[Back to top] Molecular Modeling of the
Neurohypophyseal Receptor/Atosiban Complexes
Magdalena
J. Slusarz, Rafal_ Slusarz, Rajmund Kazmierkiewicz Jerzy Trojnar , Kazimierz
Wisniewski and Jerzy Ciarkowski
The
neurohypophyseal nonapeptide hormone oxytocin (OT) is the strongest uterotonic
substance known and is responsible for the initiation of labor. Conversely,
oxytocin antagonists blocking uterine OT receptor can suppress uterus
contraction. In this paper we describe a computer simulated docking pertinent
to affinity of an oxytocin antagonist atosiban towards OT receptor, versus
vasopressin V1a and V2 receptors.
[Back to top] Fused Rola Protein Enhances b-Glucoronidase Activity 50-Fold:
Implication for Rola Mechanism of Action
Leila
Maria G. Barros , Rosane H. Curtis ,
Antônio Américo B. Viana , Laura Campos
and Mauro Carneiro
We report that the
plant oncoprotein RolA from Agrobacterium rhizogenes acts to stabilize b- glucoronidase (Gus) when the two proteins
are expressed as a fusion protein in transformed tobacco. The observed 50-fold
increase of Gus activity was shown to be related to protein accumulation, with
no significant changes in mRNA abundance, kinetic properties of the enzyme and
thermostability. The entire RolA sequence is essential to achieve the full
effect since both the N-terminal region, spanning a putative reverse
signal-anchor and nuclear targeting sequences, or the contiguous C-terminal
portion were shown to increase Gus activity only 10-fold. A possible
interference of RolA in the protein degradation pathway regulated by auxin is
discussed.
[Back to top] Monitoring Bone Loss Using Elisa
and Surface Plasmon Resonance (Spr) Technology
Feng-Di
T. Lung , Huey-Yi Chen and Hsing-Tzu
Lin
Osteoporosis
influences the health of the females who are in menopause phase. The techniques
to detect the markers of bone turnover is very important for preventing
osteoporosis. ELISA was developed for detection of urinary N-telopeptide (NTx)
as an osteoporosis marker. Our aim is to develop a sensitive method to detect
NTx excretion using surface plasmon resonance (SPR). Samples collected were
assayed and results suggest that our SPR-based method is promising for
monitoring bone loss.
[Back to top] Arrhenius Analysis of the
Electrophorus Electricus Acetylcholinesterase-Catalyzed Hydrolysis of
Acetylthiocholine
Jesse
Oakes, Tina Nguyen and B. Mark Britt
Ellman’s method
was used to determine the Michaelis-Menten parameters for the hydrolysis of acetylthiocholine
by Electrophorus electricus acetylcholinesterase from 12 to 37°C. Arrhenius
analysis revealed that the activation energy for formation of the
enzyme/substrate complex is 22.2 ± 1.1 kJ/mole. The Arrhenius plot of kcat
is markedly curved and attributed to comparable rates of acylation and
deacylation due to the absence of evidence for a temperature-dependent enzyme
conformational change by differential scanning calorimetry.
[Back to top] Purification and Crystallization
of A Lysr-Type Transcriptional Regulator Cbnr From Ralstonia Eutropha Nh9
Shin
Muraoka , Rumi Okumura , Yoshitaka Uragami , Takamasa Nonaka , Naoto Ogawa ,
Kiyotaka Miyashita and Toshiya Senda
CbnR, a LysR-type
transcriptional regulator from Ralstonia eutropha NH9, has been crystallized by
the vapor-diffusion method. It is intriguing to note that the different mixing
ratios between the protein and reservoir solutions resulted in the different
crystal forms. These crystals have the symmetry of the orthorhombic system with
space groups P21212 and P212121.