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Protein
& Peptide Letters
ISSN: 0929-8665
Protein & Peptide Letters
Volume 16, Number 2, 2009
Contents
Regular Papers
Synthesis of 1,1-Dioxobenzo[b]thiophene-2-ylmethyloxycarbonyl
(Bsmoc) Protected N-Methyl Amino Acids by Reduction
of Bsmoc-5-Oxazoli-dinones and Their Use in Peptide Synthesis
Pp. 105-111
C. Gundala, S.J. Tantry, S.A. Naik and
V.V. Sureshbabu
[Abstract] [Purchase
Article] [PMID:
19200031 PubMed - indexed for MEDLINE]
Stabilization of Neutral NH2-R-COOH
Form of the Antihypertensive Peptides L-Valyl-
L-Prolyl- L-Proline
and L Isoleucyl-
L-Prolyl- L-Proline
Pp. 112-115
T. Kolev, B.B. Koleva, I. Stoineva,
B. Jakimova and B. Tchorbanov
[Abstract]
[Purchase Article]
[PMID:
19200032 PubMed - indexed for MEDLINE]
Medicinal Plants: A Natural Chaperones
Source for Treating Neurological Disorders Pp.
116-120
B. Kastenholz and D.E. Garfin
[Abstract] [Purchase
Article]
[PMID:
19200033 PubMed - indexed for MEDLINE]
Large Scale Refolding and Purification
of the Catalytic Domain of Human BACE-2 Produced in E.
coli Pp. 121-131
T.L. Emmons, A.M. Mildner, J.M. Lull, J.W.
Leone, H.D. Fischer, R.L. Heinrikson and A.G. Tomasselli
[Abstract] [Purchase
Article]
[PMID:
19200034 PubMed - indexed for MEDLINE]
Active Form of Neuroprotective Humanin,
HN, and Inactive Analog, S7A-HN, Are Monomeric and Disordered
in Aqueous Phosphate Solution at pH 6.0; No Correlation of
Solution Structure with Activity Pp. 132-137
F. Arisaka, T. Arakawa, T. Niikura and
Y. Kita
[Abstract] [Purchase
Article]
[PMID:
19200035 PubMed - indexed for MEDLINE]
Stabilities of 67Ga-
and 111In-Labeled Transferrin
In Vitro Pp. 138-142
Y. Ohtake, A. Maruko, Y. Kuwahara, M. Fukumoto
and Y. Ohkubo
[Abstract] [Purchase
Article]
[PMID:
19200036 PubMed - indexed for MEDLINE]
Application of ‘HESH’ Descriptors
for the Structure-Activity Relationships of Antimicrobial
Peptides Pp. 143-149
M. Shu, Y. Jiang, L. Yang, Y. Wu, H. Mei
and Z. Li
[Abstract] [Purchase
Article]
[PMID:
19200037 PubMed - indexed for MEDLINE]
Interaction Models of a Series of Oxadiazole-Substituted
α-
Isopropoxy Phenylpropanoic Acids Against PPARα
and PPARγ:
Molecular Modeling and Comparative Molecular Similarity Indices
Analysis Studies Pp. 150-162
F. Cheng, J. Shen, X. Xu, X. Luo, K. Chen,
X. Shen and H. Jiang
[Abstract] [Purchase
Article]
[PMID:
19200038 PubMed - indexed for MEDLINE]
A Further Step Toward an Optimal Ensemble
of Classifiers for Peptide Classification, a Case Study: HIV
Protease Pp. 163-167
L. Nanni and A. Lumini
[Abstract] [Purchase
Article]
[PMID:
19200039 PubMed - indexed for MEDLINE]
Different Regulation Modes of Calcineurin
Regulatory Subunit on Its Catalytic Subunit with RII Peptide
and Tau as Substrates Pp. 168-172
D.-y. Yu, N. Qiao, P. Liu and Q.
Wei
[Abstract] [Purchase
Article]
[PMID:
19200040 PubMed - indexed for MEDLINE]
Purification and Characterization of
an Anticalcifying Protein from the Seeds of Trachyspermum
ammi (L.) Pp. 173-181
T. Kaur, R.K. Bijarnia, S.K. Singla and
C. Tandon
[Abstract] [Purchase
Article]
[PMID:
19200041 PubMed - indexed for MEDLINE]
Interfacial Effects on the Conformation
of Amyloid-Beta Peptide Pp. 182-188
N.W. Seidler and J.D. Eklund
[Abstract] [Purchase
Article]
[PMID:
19200042 PubMed - indexed for MEDLINE]
Solution Structure of Synbindin Atypical
PDZ Domain and Interaction with Syndecan-2 Pp.
189-195
S. Fan, Y. Feng, Z. Wei, B. Xia and
W. Gong
[Abstract] [Purchase
Article]
[PMID:
19200043 PubMed - indexed for MEDLINE]
Crystallization Reports
Trypanothione Reductase from Leishmania infantum:
Cloning, Expression, Purification, Crystallization and Preliminary
X-Ray Data Analysis Pp. 196-200
P. Baiocco, S. Franceschini, A. Ilari and
G. Colotti
[Abstract] [Purchase
Article]
[PMID:
19200044 PubMed - indexed for MEDLINE]
Purification and Characterization of
Human Brain Serine Racemase Expressed in Moderately Halophilic
Bacteria Pp. 201-206
C. Nagayoshi, M. Ishibashi and M.
Tokunaga
[Abstract] [Purchase
Article]
[PMID:
19200045 PubMed - indexed for MEDLINE]
Purification and Characterization of
L-Phenylalanine Aminopeptidase from Chick-Pea Cotyledons (Cicer
arietinum L.) Pp. 207-212
M. Marinova, A. Dolashki, F. Altenberend,
S. Stevanovic, W. Voelter and B. Tchorbanov
[Abstract] [Purchase
Article]
[PMID:
19200046 PubMed - indexed for MEDLINE]
Preliminary Crystallographic Study of
Hemoglobin from Buffalo (Bubalus bubalis): A Low
Oxygen Affinity Species Pp. 213-215
M. Balasubramanian, P.S. Moorthy, K. Neelagandan
and M.N.G. Ponnuswamy
[Abstract]
[Purchase
Article] [PMID:
19200047 PubMed - indexed for MEDLINE]
Abstracts
[Back to top]
[Purchase
Article] [PMID:
19200031 PubMed - indexed for MEDLINE]
Synthesis of 1,1-Dioxobenzo[b]thiophene-2-ylmethyloxycarbonyl
(Bsmoc) Protected N-Methyl Amino Acids by Reduction
of Bsmoc-5-Oxazoli-dinones and Their Use in Peptide Synthesis
C. Gundala, S.J. Tantry, S.A. Naik and
V.V. Sureshbabu
The synthesis of Bsmoc-N-methyl amino acids
is presented. The first step involves p-toluenesulfonic
acid (TsOH) catalysed condensation of a Bsmoc-amino acid with
paraformaldehyde to furnish N-Bsmoc-5-oxazolidinone
under MW irradiation. This intermediate is reduced to the
corresponding N-methyl amino acid using triethylsilane
(Et3SiH) and trifluoroacetic
acid (TFA) at r.t. The N-methyl amino acids are converted
into corresponding acid fluorides using di-ethylaminosulfur
trifluoride (DAST) and employed as coupling agents in the
synthesis of dipeptides. The peptide coupling was mediated
by KOAt in CH2Cl2.
[Back
to top]
[Purchase
Article]
[PMID:
19200032 PubMed - indexed for MEDLINE]
Stabilization of Neutral NH2-R-COOH
Form of the Antihypertensive Peptides L-Valyl-
L-Prolyl- L-Proline
and L Isoleucyl-
L-Prolyl- L-Proline
T. Kolev, B.B. Koleva, I. Stoineva, B. Jakimova
and B. Tchorbanov
Spectroscopic and structural elucidation of the peptides
L-Valyl-L-Prolyl-L-Proline
(1) and L-Isoleucyl-L-Prolyl-L-Proline
(2) are reported on the basis of experimental
linear-polarized IR-spectroscopy in solid-state, 1H-NMR
data and DFT. Curiously, the experimental data shown that
both peptides stabilized in solution and in solid-state neutral
H2N-R-COOH form. Conformational
analysis made, shown two strong intramolecular NH2…O=C-N(Amide)
and O=C-OH…NH2 hydrogen
bonds with lengths of 2.979 Å and 2.475 Å in (1)
and 2.599 Å and 2.507 Å in (2)
respectively. The presence of the Pro-Pro fold resulted
to strong steric effect leading to the stabilization of free
COOH and NH2 groups. The
Erel values of zwitterion
form are significant higher than the neutral forms with a
difference of 1.2 and 0.9 kJ/mol. The manner of interaction
of the peptides with angiotensin-I converting enzyme is proposed.
[Back
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[Purchase
Article] [PMID:
19200033 PubMed - indexed for MEDLINE]
Medicinal Plants: A Natural Chaperones Source for
Treating Neurological Disorders
B. Kastenholz and D.E. Garfin
Currently, no pharmaceuticals for the etiological
treatment of neurodegenerative protein-misfolding diseases
(e.g., ALS, Alzheimer’s or prion diseases) are available.
In this brief communication the development of chaperone-based
medications from medicinal plants (e.g., Ginkgo biloba)
are reviewed as referred to specific protein-protein interactions
of plant metallochaperones and human enzymes. It is indicated
that bioactive copper chaperones for superoxide dismutase
isolated from medicinal plants may be lead molecules for drug
development in several diseases concerning metal ion metabolisms
of man and animals.
[Back
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[Purchase
Article] [PMID:
19200034 PubMed - indexed for MEDLINE]
Large Scale Refolding and Purification of the Catalytic
Domain of Human BACE-2 Produced in E. coli
T.L. Emmons, A.M. Mildner, J.M. Lull, J.W.
Leone, H.D. Fischer, R.L. Heinrikson and A.G. Tomasselli
Evidence for a key role of beta-amyloid
(Aβ)
in Alzheimer's disease has led to considerable interest in
potential therapeutic strategies targeting enzymes involved
in processing the amyloid precursor protein (APP). Beta-site
APP Cleaving Enzyme (BACE or β-secretase)
is a membrane bound aspartyl protease that has been shown
to be directly involved in Aβ
production and, therefore, is at the forefront of therapeutic
targets in the treatment of Alzheimer’s disease. BACE-2,
an enzyme closely related to BACE, regulates Aβ
production in a manner antagonistic to BACE, suggesting that
non-selective inhibition of BACE-2 by BACE inhibitors might
impair the lowering of Aβ.
The design of BACE inhibitors that do not inhibit BACE-2 would
be enhanced by structural and kinetic studies, efforts that
typically demand consider-able amounts of both enzymes. A
BACE-2 construct containing 19 residues of the BACE prosegment
followed by the BACE-2 catalytic domain sequence, Asp36…..Trp477,
was produced in E. coli inclusion bodies (IB) at
110-140 mg/L cell culture. Exploration of a variety of refolding
conditions resulted in an efficient method for refolding the
resulting pro-BACE-2 construct, and this protein undergoes
facile autocatalytic cleavage, optimal at pH 4, at the Leu40-↓
-Ala41 bond. Refolded
BACE-2 was purified by anion exchange, molecular sieve, and
affinity chromatographies, yielding 105 mg of homogeneous
enzyme (kcat/ Km
= 1.2 x 104 x M-1
x sec-1) from 8 liters of
E. coli cell culture.
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[Purchase
Article] [PMID:
19200035 PubMed - indexed for MEDLINE]
Active Form of Neuroprotective Humanin, HN, and Inactive
Analog, S7A-HN, Are Monomeric and Disordered in Aqueous Phosphate
Solution at pH 6.0; No Correlation of Solution Structure with
Activity
F. Arisaka, T. Arakawa, T. Niikura and
Y. Kita
A novel neuroprotective peptide, Humanin (HN), has a
strong tendency to aggregate in phosphate-buffered saline.
Here we attempted to reduce aggregation employing an aqueous
phosphate solution, without NaCl, at pH 6.0 and low peptide
concentrations wherever possible. Such a condition, though
not fully physiological, allowed us to determine the secondary
structure and molecular weight of the peptides. Comparison
of a parent HN peptide, an inactive analog (S7A-HN) and a
1000-fold more active analog (S14G-HN) showed no apparent
differences in the secondary structure. These peptides were
all disordered over the wide range of peptide concentration.
Sedimentation analysis was done only for HN and S7A-HN and
showed aggregation into soluble oligomers in 20 mM phosphate
at pH 6.0. Aggregation was greatly suppressed in 5 mM phosphate
at the same pH in terms of aggregate size, with the formation
of smaller oligomers. Sedimentation velocity experiments at
60,000 rpm in 5 mM phosphate at pH 6.0 showed that both HN
and S7A-HN distributed into soluble aggregates that sedimented
to the bottom of the cell and low molecular weight species
that approached sedimentation equilibrium. The mass of this
low molecular weight species was determined by sedimentation
equilibrium to be close to monomers for both peptides. Thus,
these results clearly demonstrate that the active HN and inactive
S7A-HN are identical in structure and hence there is no apparent
correlation between solution structure and
biological activity.
[Back
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[Purchase
Article] [PMID:
19200036 PubMed - indexed for MEDLINE]
Stabilities of 67Ga-
and 111In-Labeled Transferrin
In Vitro
Y. Ohtake, A. Maruko, Y. Kuwahara, M. Fukumoto
and Y. Ohkubo
We attempted to develop a stable radiolabeled
transferrin (Tf) useful in experimental studies related to
Tf receptor. 67Ga and 111In
were used as labeling radioisotopes. The results from gel
chromatography, dialysis, and electrophoresis showed that
111In-DTPA-Tf
was the most stable among the radiolabeled Tfs examined in
the present study. 111In-DTPA-Tf
was also the most stable radiolabeled transferrin in the blood.
[Back
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[Purchase
Article] [PMID:
19200037 PubMed - indexed for MEDLINE]
Application of ‘HESH’ Descriptors for
the Structure-Activity Relationships of Antimicrobial Peptides
M. Shu, Y. Jiang, L. Yang, Y. Wu, H. Mei
and Z. Li
In this paper, HESH, which was a new set of amino acid
descriptors including Hydrophobic, Electronic, Steric and
Hydrogen bond contribution properties, were derived from multi-dimensional
properties of 20 coded amino acids. The quantitative structure-activity
relationship (QSAR) of 101 synthetic cationic antimicrobial
polypeptides (CAMELs) was then characterized with HESH scales
and studied by genetic algorithm-partial least square (GA-PLS)
method. It was found that the robust QSAR model constructed
with electronic and hydrophobic properties parameters of HESH
descrip-tors was a better one. Through further analysis, electronic
and hydrophobic properties of the 3rd, 6th, 7th, 11th and
12th residue of CAMELs sequence made high contribution to
antimicrobial potencies. Based on this PLS model, a series
of cationic antimicrobial peptides (AMPs), with relatively
high antimicrobial activity was designed. Meanwhile, a robust
QSAR model with favorable predictive capability for 34 antimicrobial
peptides was constructed with HESH descriptors. The results
showed that HESH descriptors had many obvious advantages,
for it contains abundant information and its physico-chemical
characteristics are clear and easily explained. The developed
descriptors can be further expanded for the larger sets of
biologically activities peptides and can serve as a useful
quantitative tool for the rational design and discovery of
antibiotics.
[Back
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[Purchase
Article] [PMID:
19200038 PubMed - indexed for MEDLINE]
Interaction Models of a Series of Oxadiazole-Substituted
α-
Isopropoxy Phenylpropanoic Acids Against PPARα
and PPARγ:
Molecular Modeling and Comparative Molecular Similarity Indices
Analysis Studies
F. Cheng, J. Shen, X. Xu, X. Luo, K. Chen,
X. Shen and H. Jiang
Molecular recognition of a series of oxadiazole-substituted
α-isopropoxy
phenylpropanoic acids by PPARα
and PPARγ
was investigated by using molecular modeling and 3D-QSAR analyses.
The binding models of these compounds were determined by hydrophobic
property analyses and molecular docking procedure FlexX. It
was found that the hydrophilic heads of these compounds form
four specific conserved hydrogen bonds with the ligand binding
pockets of PPARα
and PPARγ,
which results in fixed head conformations. On the contrary,
their hydrophobic tails adopt different configurations to
make contacts with hydrophobic region. The oxadiazole-ring-related
hydrogen bond interactions well elucidate the structural features
governing the different binding behavior of these agonists
against PPARα
and PPARγ.
Based on these active conformations, highly predictive comparative
molecular similarity indices analysis (CoMSIA) models were
derived, which not only is consistent with the experimental
results but also could be mapped back to the receptor topology
and the ligand-receptor interaction models. The simulation
results reveal the structure-activity relationship of these
com-pounds at the molecular level and provide new insights
for the design of novel potent PPARα
and PPARγ
dual agonists.
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[Purchase
Article] [PMID:
19200039 PubMed - indexed for MEDLINE]
A Further Step Toward an Optimal Ensemble of Classifiers
for Peptide Classification, a Case Study: HIV Protease
L. Nanni and A. Lumini
The focuses of this work are: to propose
a novel method for building an ensemble of classifiers for
peptide classification based on substitution matrices; to
show the importance to select a proper set of the parameters
of the classifiers that build the ensemble of learning systems.
The HIV-1 protease cleavage site prediction problem is here
studied.
The results obtained by a blind testing protocol are reported,
the comparison with other state-of-the-art approaches, based
on ensemble of classifiers, allows to quantify the performance
improvement obtained by the systems proposed in this paper.
The simulation based on experimentally determined protease
cleavage data has demonstrated the success of these new ensemble
algorithms. Particularly interesting it is to note that also
if the HIV-1 protease cleavage site prediction problem is
considered linearly separable we obtain the best performance
using an ensemble of non-linear classifiers.
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[Purchase
Article] [PMID:
19200040 PubMed - indexed for MEDLINE]
Different Regulation Modes of Calcineurin Regulatory
Subunit on Its Catalytic Subunit with RII Peptide and Tau
as Substrates
D.-y. Yu, N. Qiao, P. Liu and Q.
Wei
Calcineurin (CN) is a heterodimer of a catalytic
subunit, calcineurin A (CNA), and a regulatory subunit (CNB).
Here, we find that the mechanism by which CNB regulates CNA
depends on the substrate involved. The regulation mechanism
involving tau and its truncation segments is distinct from
that involving RII peptide, and the efficiencies of CNA to
dephosphorylate tau are constant regardless of whether CNB
was present or not. The findings shed some light on the role
of CNB in controlling phosphorylation of tau in vivo
and the pathogenesis of tauopathies such as Alzheimer’s
Disease.
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[Purchase
Article] [PMID:
19200041 PubMed - indexed for MEDLINE]
Purification and Characterization of an Anticalcifying
Protein from the Seeds of Trachyspermum ammi (L.)
T. Kaur, R.K. Bijarnia, S.K. Singla and
C. Tandon
Till date various plants extract have been studied to
reduce the incidence of urolithiasis but the identification
of naturally occurring calcium oxalate (CaOx) inhibitory biomolecules
from plants was hampered in past by limitation in identification
method. The present study is aimed at examining the efficacy
of Trachyspermum ammi on CaOx crystallization in
vitro and further by combining conventional biochemical
methods with recent advances in mass spectrometry, a novel
calcium oxalate (CaOx) crystal growth inhibitor was purified
from the seeds of Trachyspermum ammi. An anticalci-fying
protein from the seeds of Trachyspermum ammi was
purified by three step purification scheme; ammonium sulphate
fractionation, anion exchange chromatography and molecular
sieve chromatography based on its ability to inhibit calcium
oxalate crystallization in vitro. An anticalcifying
protein having molecular weight 107 kDa and isolectric point
6.2 was isolated. Amino acid analysis of Trachyspermum
ammi anticalcifying protein (TAP) showed abundant presence
of acidic amino acids (Asp and Glu). Matrix-assisted laser
desorption/ionization-time-of-flight mass spectrometry of
TAP showed similarities with an unnamed protein product of
Vitis vinifera (CAO23876) after matching peptide
mass fingerprints in MASCOT search engine. Two EF hand domains
were identified in unnamed protein product of Vitis vinifera
(CAO23876) by SMART normal module. Due to a significant similarity
of TAP with unnamed protein product of Vitis vinifera,
presence of two EF hand domains in TAP was anticipated, signifying
its calcium binding properties which is a feature of most
kidney stone inhibitory proteins.
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[Purchase
Article] [PMID:
19200042 PubMed - indexed for MEDLINE]
Interfacial Effects on the Conformation of Amyloid-Beta
Peptide
N.W. Seidler and J.D. Eklund
We examined the effects of air-water and water-sevoflurane
interfaces on conformational properties of amyloid-β
peptide (ABP). Fractions were extracted from sub-interfacial
(air-water) and supra-interfacial (water-sevoflurane) layers
and compared with aqueous bulk layers using fluorescence properties
of ABP provided by a single tyrosine. The observations suggest
that interfacial ABP may be more disordered than bulk ABP.
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[Purchase
Article] [PMID:
19200043 PubMed - indexed for MEDLINE]
Solution Structure of Synbindin Atypical PDZ Domain
and Interaction with Syndecan-2
S. Fan, Y. Feng, Z. Wei, B. Xia and
W. Gong
Synbindin is one component of Transport
protein particle (TRAPP) complexes. In the hippocampal neurons,
synbindin binds syndecan-2 by its atypical PDZ domain (APD)
and may regulate the formation of dendritic spines. To investigate
the interaction of synbindin and syndecan-2, we determined
the solution structure of the synbindin APD by NMR. The structure
of APD is different from the classical canonical PDZ domains
by lacking the typical aA helix and the signature sequence
Gly-Ψ-Gly-Ψ.
These differences indicate that APD may not bind syndecan-2
with the typical binding mode of other PDZ domain proteins.
In NMR titration experiments, APD do not bind with the C-terminal
TKEFYA peptide of syndecan-2, but can interact with the 32-residue
cytoplasmic domain of syndecan-2 very weakly.
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[Purchase
Article] [PMID:
19200044 PubMed - indexed for MEDLINE]
Trypanothione Reductase from Leishmania infantum:
Cloning, Expression, Purification, Crystallization and Preliminary
X-Ray Data Analysis
P. Baiocco, S. Franceschini, A. Ilari and
G. Colotti
The most promising targets for Leishmania-specific
drug design are two key enzymes involved in the unique thiol-based
metabolism, common to all parasites of the Trypanosomatidae
family: trypanothione synthetase (TryS) and trypanothione
reductase (TR). Recently, new inhibitors of TR have been identified
such as polyamines and tricyclic compounds. The knowledge
of the three-dimensional structure of Leishmania TR will shed
light on the mechanism of interaction of these inhibitors
with TR and will be the starting point to design novel lead
candidates to facilitate the development of new effective
and affordable drugs. Trypanothione reductase from Leishmania
infantum has been cloned, expressed in E. coli
and purified. Crystals were obtained at 294 K by the hanging
drop vapour diffusion method using ammonium sulfate as precipitant
agent and diffract to better than 2.95 Å resolution
using a synchrotron radiation source. The crystals exhibit
an unusually high solvent content of 74 %, belong to the tetragonal
space group P41 with units cell parameters a=b=103.45 Å,
c=192.62 Å and two molecules in the asymmetric unit.
The protein X-ray structure has been solved by Molecular Replacement
and the model is under construction.
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[Purchase
Article] [PMID:
19200045 PubMed - indexed for MEDLINE]
Purification and Characterization of Human Brain
Serine Racemase Expressed in Moderately Halophilic Bacteria
C. Nagayoshi, M. Ishibashi and M.
Tokunaga
We have successfully expressed an active
human brain serine racemase (hSR) with His-tag using moderate
halophile. The purified His-hSR showed high elimination and
racemization activities on L-serine: the elimination activity
was 2.6-fold higher than racemization activity. Both enzyme
activities showed an optimum reaction pH at around 9.0 and
were stimulated 5- to 7-fold by such divalent cations as Mg++,
Mn++ and Ca++.
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[Purchase
Article] [PMID:
19200046 PubMed - indexed for MEDLINE]
Purification and Characterization of L-Phenylalanine
Aminopeptidase from Chick-Pea Cotyledons (Cicer arietinum
L.)
M. Marinova, A. Dolashki, F. Altenberend, S.
Stevanovic, W. Voelter and B. Tchorbanov
Chick-pea (Cicer arietinum L.)
cotyledons are unique source of aminopeptidase – 8-9
U/g cotyledons was observed using L-leucine-p-nitroanilide
as substrate. The aminopeptidase was purified (65 kDa, pI
4.8 ) reaching a specific activity of 220 U/mg at pH 7.0-7.2
and 35-40°C. The determined constant of specificity kcat/Km
during hydrolysis of N-unsubstituted amino acid-p-nitroanilides
showed a decrease order: Phe>Leu>Pro>Ile>Val>Ala.
The enzyme was strongly inhibited by p-chloromercuribenzoic
acid as well as in a competitive rate by the antihypertensive
peptides Ile-Pro-Pro and Val-Pro-Pro.
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[Purchase
Article] [PMID:
19200047 PubMed - indexed for MEDLINE]
Preliminary Crystallographic Study of Hemoglobin
from Buffalo (Bubalus bubalis): A Low Oxygen Affinity
Species
M. Balasubramanian, P.S. Moorthy, K. Neelagandan
and M.N.G. Ponnuswamy
Hemoglobin is a tetrameric, iron-containing metalloprotein,
which plays a vital role in the transportation of oxygen from
lungs to tissues and carbon dioxide back to lungs. Though
good amount of work has already been done on hemoglobins,
the scarcity of data on three dimensional structures pertaining
to low oxygen affinity hemoglobins from mammalian species,
motivated our group to work on this problem specifically.
Herein, we report the preliminary crystallographic analysis
of buffalo hemoglobin, which belongs to low oxygen affinity
species. The buffalo blood was collected, purified by anion
exchange chromatography and crystallized with PEG 3350 using
50mM phosphate buffer at pH 6.7 as a precipitant by hanging
drop vapor diffusion method. Data collection was carried out
using mar345dtb image plate detector system. Buffalo
hemoglobin crystallizes in orthorhombic space group P212121
with one whole biological molecule (α2β2)
in the asymmetric unit with cell dimensions a=63.064Å,
b=74.677Å, c=110.224Å.
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