|
Protein
& Peptide Letters
ISSN: 0929-8665
Protein & Peptide Letters
Volume 16, Number 3, 2009
Contents
Editorial Pp. 216
A. Sakudo
[PMID: 19275733 PubMed - indexed for MEDLINE]
Fundamentals of Prion Diseases and Their Involvement
in the Loss of Function of Cellular Prion Protein Pp.
217-229
A. Sakudo and K. Ikuta
[Abstract] [Purchase
Article] [PMID:
19275734 PubMed - indexed for MEDLINE]
Properties and Pathogenicity of Prion-Derived
Peptides Pp. 230-238
N. Vassallo
[Abstract] [Purchase
Article] [PMID:
19275735 PubMed - indexed for MEDLINE]
Role of Cellular Prion Proteins in the
Function of Macrophages and Dendritic Cells Pp.
239-246
K. Nitta, A. Sakudo, J. Masuyama, G. Xue,
K. Sugiura and T. Onodera
[Abstract] [Purchase
Article] [PMID:
19275736 PubMed - indexed for MEDLINE]
Uptake and Dynamics of Infectious Prion
Protein in the Intestine Pp. 247-255
Y. Ano, A. Sakudo, H. Nakayama and
T. Onodera
[Abstract] [Purchase
Article] [PMID:
19275737 PubMed - indexed for MEDLINE]
Recent Advances in Cell-Free PrPSc
Amplification Technique Pp. 256-259
R. Atarashi
[Abstract] [Purchase
Article] [PMID:
19275738 PubMed - indexed for MEDLINE]
Prospects for Preventative Vaccines Against
Prion Diseases Pp. 260-270
S. Sakaguchi
[Abstract] [Purchase
Article] [PMID:
19275739 PubMed - indexed for MEDLINE]
Life Cycle of Yeast Prions: Propagation
Mediated by Amyloid Fibrils Pp. 271-276
Y. Inoue
[Abstract] [Purchase
Article] [PMID:
19275740 PubMed - indexed for MEDLINE]
General Articles
Regular Papers
Trypsin-Chymotrypsin Inhibitors from Vigna
mungo Seeds Pp. 277-284
A.H.K. Cheung, J.H. Wong and T.B.
Ng
[Abstract] [Purchase
Article] [PMID:
19275741 PubMed - indexed for MEDLINE]
Syntheses of NPTX-594 Analogs with Thiol-Containing
Fluorophores to Develop a Probe for Analysis of Binding Mode
Between Spider Toxins and Glutamate Receptors Pp.
285-288
T. Nishimaru, Y. Yamaguchi and T.
Wakamiya
[Abstract] [Purchase
Article] [PMID:
19275742 PubMed - indexed for MEDLINE]
Determination of Mutation Pattern in
Human Androgen Receptor by Means of Amino-Acid Pair Predictability
Pp. 289-296
S. Yan and G. Wu
[Abstract] [Purchase
Article] [PMID:
19275743 PubMed - indexed for MEDLINE]
Stereochemical Preference in the Reactions
of N-Protected L Amino Acid 1-Hydroxybenzotriazole
Esters with Racemic Amino Acid Derivatives Pp.
297-300
T. Miyazawa, A. Ozawa, M. Furuhashi and
T. Munegumi
[Abstract] [Purchase
Article] [PMID:
19275744 PubMed - indexed for MEDLINE]
Screening of SMG7-Binding Peptides by
Combination of Phage Display and Docking Simulation Analysis
Pp. 301-305
M. Zahed, T. Suzuki, A. Suganami, H. Sugiyama,
K. Harada, M. Takiguchi, Y. Tamura and N. Suzuki
[Abstract] [Purchase
Article] [PMID:
19275745 PubMed - indexed for MEDLINE]
The Coiled-Coil Neck Domain of Human
Pulmonary Surfactant Protein D Drives Trimerization and Stabilization
of Thioredoxin, a Heterologous Non-Collagenous Protein
Pp. 306-311
P. Li, J.Y. Zhou, Y.Y. Zhou, C.D. Qian,
O. Li, H. Min and X.C. Wu
[Abstract] [Purchase
Article] [PMID:
19275746 PubMed - indexed for MEDLINE]
Total Synthesis of Cyclosporin O: Exploring
the Utility of Bsmoc-NMe-Amino Acid Fluorides and
KOAt Pp. 312-319
V.V. Sureshbabu, S.J. Tantry, G. Chennakrishnareddy
and G. Nagendra
[Abstract] [Purchase
Article] [PMID:
19275747 PubMed - indexed for MEDLINE]
Molecular Cloning of Grass Carp Growth
Hormone Receptor and Its Functional Interaction with Silver
Carp Growth Hormone Pp. 320-323
W. Hu, X. Chen, G. Yu, Y. Chen, Y. Shen,
Y. Zhang and Y. Gong
[Abstract] [Purchase
Article] [PMID:
19275748 PubMed - indexed for MEDLINE]
Studies on the Acid Induced Unfolding
of Human Serum Albumin Pp. 324-332
P. Salahuddin
[Abstract] [Purchase
Article] [PMID:
19275749 PubMed - indexed for MEDLINE]
Crystallization Reports
Crystallization and Preliminary X-Ray Analysis
of the Splice Variant of Human Ankyrin Repeat and Suppressor
of Cytokine Signaling Box Protein 9 (hASB9-2) Pp.
333-335
X. Fei, Y. Zhang, X. Gu, R. Qiu, Y. Mao
and C. Ji
[Abstract] [Purchase
Article] [PMID:
19275750 PubMed - indexed for MEDLINE]
Crystallization and Preliminary X-Ray
Crystallographic Studies on SI-CLP, a Novel Human Glyco_18
Domain–Containing Protein Pp. 336-338
G. Meng, X. Bai, T.J. Green, M. Luo and
X. Zheng
[Abstract] [Purchase
Article] [PMID:
19275751 PubMed - indexed for MEDLINE]
Crystallization and Preliminary Crystallographic
Analysis of Recombinant Human Calcyphosine Pp.
339-341
H. Dong, Z. Lou, X. Xu, D. Su, X. Zhou,
X. Li and M. Bartlam
[Abstract] [Purchase
Article] [PMID:
19275752 PubMed - indexed for MEDLINE]
Abstracts
[Back to top]
[PMID:
19275733 PubMed - indexed for MEDLINE]
Editorial:
Recently, several detection methods for prion and/or
prion protein (PrP) (including abnormal and cellular PrP)
have been developed. An important method is protein misfolding
cyclic amplification (PMCA), which enables the amplification
of abnormal PrP in vitro. Prospects for therapy or
preventative vaccine have also been explored. Accumulated
knowledge on the role of cellular PrP would provide useful
information for exploring strategies for the treatment of
prion diseases. To discuss this hot topic, scientists using
various approaches to study the pathogenesis, diagnosis, and
prevention of prion diseases were invited.
I am glad to have the honor to organize a Hot Topic issue
for Protein and Peptide Letters and to experience
working with eminent scientists to review research on prion
diseases. This issue covers the broad topic of prion biology
and includes articles on the following topics: fundamental
knowledge and possible pathogenesis of prion diseases written
by myself and Prof. Kazuyoshi Ikuta, recent studies on a neurocytotoxicity
model of a PrP-derived peptide written by Dr. Neville Vassallo,
the role of cellular PrP in functions of macrophage and dendritic
cells written by Prof. Takashi Onodera and colleagues, uptake
of abnormal PrP in the intestines written by Prof. Hiroyuki
Nakayama and colleagues, abnormal PrP amplification by PMCA
written by Dr. Ryuichiro Atarashi, prospects for preventative
vaccine against prion diseases written by Prof. Suehiro Sakaguchi,
and yeast prions written by Dr. Yuji Inoue. Hopefully, readers
will enjoy this issue, obtain useful information for their
own research, and be inspired with new ideas for future research
on prion biology.
Akikazu Sakudo
Guest Editor
Protein & Peptide Letters
Department of Virology
Center for Infectious Disease Control
Research Institute for Microbial Diseases
Osaka University, Osaka
Japan
[Back to top]
[Purchase
Article] [PMID:
19275734 PubMed - indexed for MEDLINE]
Fundamentals of Prion Diseases and Their Involvement
in the Loss of Function of Cellular Prion Protein
A. Sakudo and K. Ikuta
Prion diseases are fatal degenerative disorders whose
features include the accumulation of abnormal isoform of prion
protein (PrPSc), vacuolation,
and astrocytosis in the brain. After a prion infection, the
cellular isoform of prion protein (PrPc)
is converted into PrPSc,
resulting in PrPc deficiency
and PrPSc accumulation in
the brain. These changes are major etiological events, thought
to be closely related to the pathogenesis of prion diseases,
and used as an index for diagnosis. Studies using recently
developed research tools such as transgenic and knockout mice
and cell lines have shown that the accumulation of PrPSc
is not the sole factor contributing to the clinical onset
of prion diseases and that loss-of function of PrPc
by depletion leads to neuronal cell loss. Notably, PrPc
plays an important role in anti-oxidative defense and its
deficiency increases susceptibility to oxidative stress. Furthermore,
there is a possible interrelationship between Alzheimer’s
disease and prion disease through loss-of-function of PrPC,
which leads to the production of amyloid β.
In this review, we introduce research and diagnostic tools
for prion diseases and the involvement of loss-of-function
of PrPC in the pathogenicity
of prion diseases.
[Back to top]
[Purchase
Article] [PMID:
19275735 PubMed - indexed for MEDLINE]
Properties and Pathogenicity of Prion-Derived Peptides
N. Vassallo
Prion diseases are neurodegenerative disorders characterized
by a hallmark event involving the post-translational misfolding
of the normal cellular prion protein (PrPC)
into an infectious and toxic protease-resistant conformation
(PrPsc). Studies on identification
of the pathological prion species and on the mechanisms involved
in triggering neuronal death have been hampered by the heterogeneous
nature of PrPsc aggregates.
The use of synthetic PrP-derived peptides has made possible
exploration of the relationship between amino acid sequence,
biophysical structure and biological effect. Indeed, most
PrP-derived peptides replicate the fundamental aspects of
full-length PrPsc, including:
a β-sheet-rich
structure; destabilization of lipid membranes; intracellular
calcium dysregulation; increased oxidative stress; activation
of pro-apoptotic signaling pathways; and, more contentiously,
neurotoxicity dependent upon endogenous PrPC
expression. Crucially, in vivo toxicity of the important
PrP-peptides, e.g. PrP(106-126) and PrP(118-135), has additionally
been established. Therefore, the use of prion-derived peptides
facilitates the development of therapeutic strategies based
on small-molecule inhibitors of aggregation and other pharmacological
agents that protect against the lethal effect of these peptides
in vivo.
[Back to top]
[Purchase
Article] [PMID:
19275736 PubMed - indexed for MEDLINE]
Role of Cellular Prion Proteins in the Function of
Macrophages and Dendritic Cells
K. Nitta, A. Sakudo, J. Masuyama, G. Xue,
K. Sugiuraand T. Onodera
The cellular isoform of prion proteins (PrPC)
is expressed in hematopoietic stem cells, granulocytes, T
and B lymphocyte natural killer cells, platelets, monocytes,
dendritic cells, and follicular dendritic cells, which may
act as carrier cells for the spread of its abnormal isoform
(PrPSc) before manifesting
transmissible spongiform encephalopathies (TSEs). In particular,
macrophages and dendritic cells seem to be involved in the
replication of PrPSc after
ingestion. In addition, information on the role of PrPc
during phagocytotic activity in these cells has been obtained.
A recent study showed that resident macrophages from ZrchI
PrP gene (Prnp)-deficient (Prnp-/-)
mice show augmented phagocytotic activity com-pared to
Prnp+/+ counterparts.
In contrast, our study suggests that Rikn Prnp-/-
peritoneal macrophages show pseudopodium extension arrest
and up-regulation of phagocytotic activity compared to Prnp+/+
cells. Although reports regarding phagocytotic activity in
resident and peritoneal macrophages are inconsistent between
ZrchI and Rikn Prnp-/-
mice, it seems plausible that PrPC
in macrophages could contribute to maintain the immunological
environment. This review will introduce the recent progress
in understanding the functions of PrPC
in macrophages and dendritic cells under physiological conditions
and its involvement in the pathogenesis of prion diseases.
[Back to top]
[Purchase
Article] [PMID:
19275737 PubMed - indexed for MEDLINE]
Uptake and Dynamics of Infectious Prion Protein in
the Intestine
Y. Ano, A. Sakudo, H. Nakayama and
T. Onodera
Transmissible spongiform encephalopathies (TSEs) are
characterized by the accumulation of a protease-resistant
abnormal isoform of the prion protein (PrPSc),
which is converted from the cellular isoform of the prion
protein (PrPc). In the oral
transmission of prion protein, PrPSc
can invade a host body through the intestinal tract. There
is only limited information available on how the infectious
agent passes through one or several biological barriers before
it can finally reach the brain. After oral administration,
PrPSc withstands the digestive
process and may be incorporated by microfold (M) cells or
villous columnar epithelial cells in the intestine. After
entry into the intestinal epithelium, PrPSc
accumulates and is amplified in follicular dendritic cells
(FDCs) within Peyer’s patches and other isolated lymphoid
follicles possibly by an interaction with dendritic cells
or macrophages. Following accumulation in gut-associated lymphoid
tissues, PrPSc is thought
to move to the enteric nervous systems (ENS) by an interaction
with FDCs or dendritic cells. As a result of neuroinvasion
into the ENS, PrPSc spreads
to the central nervous system. In addition, an epidemiological
study suggested that most bovine spongiform encephalopathy
cases had been exposed to the agent in the first 6 months
of life. Developments of the intestinal defense and immune
system may be involved in the susceptibility to infection.
[Back to top]
[Purchase
Article] [PMID:
19275738 PubMed - indexed for MEDLINE]
Recent Advances in Cell-Free PrPSc
Amplification Technique
R. Atarashi
The development of amplification technology for abnormal
forms of prion protein in vitro has had a great impact
on the field of prion research. This novel technology has
generated new possibilities for understanding the molecular
basis of prions and for developing an early diagnostic test
for prion diseases. This review provides an overview of recent
progress in cell-free PrPSc
amplification techniques.
[Back to top]
[Purchase
Article] [PMID:
19275739 PubMed - indexed for MEDLINE]
Prospects for Preventative Vaccines Against Prion
Diseases
S. Sakaguchi
Emergence of variant type of Creutzfeldt-Jakob disease
(vCJD) in humans due to infection from bovine spongiform encephalopathy
contaminated beef and recent reports of human-to-human transmission
of vCJD via blood transfusion have raised great concern about
an epidemic of vCJD. The disease is currently difficult to
diagnose during pre-clinical stages and requires a very long
incubation period for neurological symptoms to be evident.
This therefore suggests that the disease is already latently
spreading and that opportunity for infection is thus growing
among human populations. Interestingly, passive immunization
with antibodies against prion protein (PrP), a major component
of the prion infectious agents, was shown to protect mice
from infection, indicating the possibility of prion vaccines.
However, PrP is a host protein therefore immune tolerance
to PrP has hampered development of them. Here, the so far
reported attempts to overcome the tolerance to elicit protective
immunity to prions are briefly reviewed.
[Back to top]
[Purchase
Article] [PMID:
19275740 PubMed - indexed for MEDLINE]
Life Cycle of Yeast Prions: Propagation Mediated
by Amyloid Fibrils
Y. Inoue
Currently, prion phenomena have been detected in various
organisms, in addition to mammals affected by transmissible
spongiform encephalopathies. In the budding yeast Saccharomyces
cerevisiae, various proteins have prion properties and
adopt atypical phenotypes as genetic elements, such as the
Sup35 and Ure2 proteins, corresponding to the [PSI+]
and [URE3] phenotypes, respectively. Each yeast prion
protein has a prion-forming region rich in glutamines and/or
asparagines, and can form amyloid fibrils in its prion conformation.
Studies on yeast prions have revealed that the amyloid fibrils
play critical roles in the life cycle of the yeast prion.
First, the amyloid fibril binds the normal prion protein and
catalyzes a structural conversion into the abnormal form,
the key event of the prion phenomenon. Second, the amyloid
fibril is related to the strain differences of the prion phenotypes,
by its substructural differences. Third, the number of prion
elements multiplies by the fragmentation of amyloid fibrils,
which is mediated by a chaperone system in which Hsp104 plays
a central role, and the prion elements are distributed to
the daughter cells during cell division. Moreover, heterologous
prion-prion communications may occur, probably by cross-seeding
of amyloid fibrils among different prion proteins in the same
yeast cell. Findings achieved by yeast prion studies are making
great contributions toward understanding the characteristics
of amyloid fibrils and prions.
[Back to top]
[Purchase
Article] [PMID:
19275741 PubMed - indexed for MEDLINE]
Trypsin-Chymotrypsin Inhibitors from Vigna mungo
Seeds
A.H.K. Cheung, J.H. Wong and T.B.
Ng
Three trypsin-chymotrypsin inhibitors were isolated from
seeds of the black gram (Vigna mungo) with a procedure
that entailed cation exchange chromatography on SP-Sepharose,
anion exchange chromatography on Q-Sepharose, ion exchange
chromatography by fast protein liquid chromatography (FPLC)
on Mono Q and Mono S, and gel filtration by FPLC on Superdex
75. Two of the trypsin-chymotrypsin inhibitors were adsorbed
on the first four types of chromatographic media. All three
inhibitors have a molecular mass of 16 kDa as judged by gel
filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis.
The trypsin inhibitory activity of the inhibitors was attenuated
in the presence of the reducing agent dithiothreitol. The
remaining inhibitor was unadsorbed on SP-Sepharose but adsorbed
on Q-Sepharose, Mono Q and Mono S. The protease inhibitors
did not exert any inhibitory effect on hepatoma (Hep G2) and
breast cancer (MCF 7) cells or antifungal action toward Botrytis
cinerea, Fusarium oxysporum and Mycosphaerella arachidicola.
Two of the inhibitors slightly inhibited the activity of HIV-1
reverse transcriptase, with an IC50
in the millimolar range.
[Back to top]
[Purchase
Article] [PMID:
19275742 PubMed - indexed for MEDLINE]
Syntheses of NPTX-594 Analogs with Thiol-Containing
Fluorophores to Develop a Probe for Analysis of Binding Mode
Between Spider Toxins and Glutamate Receptors
T. Nishimaru, Y. Yamaguchi and T.
Wakamiya
NPTX-594 is a neurotoxic acylpolyamine isolated from
a Madagascar Joro spider and acts as a specific blocker of
glutamate receptors (GluRs). The present study reports the
creation of novel NPTX-594 analogs with thiol-containing fluorophores
for use as visualization probes for the analysis of the binding
mode between spider toxins and GluRs, together with the result
of their cricket bioassay.
[Back to top]
[Purchase
Article] [PMID:
19275743 PubMed - indexed for MEDLINE]
Determination of Mutation Pattern in Human Androgen
Receptor by Means of Amino-Acid Pair Predictability
S. Yan and G. Wu
The mutation trend and pattern in protein are currently
studied directly using amino acid sequence, however, it would
be more efficient if the amino acid sequence is transferred
into other domains through quantification because sophisticated
mathematical tools can be applied to a numeric sequence. In
this study, we apply the amino-acid pair predictability to
quantifying the human androgen receptor with its 215 missense
point mutations to analyze which amino-acid pairs are sensitive
to mutations. The results show that 94.88% mutations occurred
at the unpredictable amino-acid pairs, 79% mutations targeted
at one or two original amino-acid pairs whose actual frequency
is larger than predicted frequency and 63.26% mutations lead
to one or two mutated amino-acid pairs with their actual frequency
smaller than predicted one.
[Back to top]
[Purchase
Article] [PMID:
19275744 PubMed - indexed for MEDLINE]
Stereochemical Preference in the Reactions of N-Protected
L Amino Acid 1-Hydroxybenzotriazole Esters with Racemic Amino
Acid Derivatives
T. Miyazawa, A. Ozawa, M. Furuhashi and
T. Munegumi
Stereochemical preference for homochiral or heterochiral
couplings was investigated in the reactions of N-protected
L-amino acid 1-hydroxybenzotriazole esters with racemic amino
acid derivatives. It was found to be dependent on the combination
of amino acid residues as the carboxyl and amino components
and the protecting groups of the amino acid residues, especially
the N-protecting groups. Very high diastereomeric
ratios were observed when t-leucine was employed
as the carboxyl component and/or proline as the amino component
and when the N-protecting group was the phthaloyl
group.
[Back to top]
[Purchase
Article] [PMID:
19275745 PubMed - indexed for MEDLINE]
Screening of SMG7-Binding Peptides by Combination
of Phage Display and Docking Simulation Analysis
M. Zahed, T. Suzuki, A. Suganami, H. Sugiyama,
K. Harada, M. Takiguchi, Y. Tamura and N. Suzuki
We screened SMG7-binding peptides with phage display
and docking simulation analysis. Although a consensus motif
was absent in the phage display-derived candidates, we succeeded
to find a peptide CDDRPPKSC, which can bind specifically to
SMG7. We conclude that docking simulation helps to find high-affinity
peptides efficiently, even if the phage display-screened candidates
lack a consensus region.
[Back to top]
[Purchase
Article] [PMID:
19275746 PubMed - indexed for MEDLINE]
The Coiled-Coil Neck Domain of Human Pulmonary Surfactant
Protein D Drives Trimerization and Stabilization of Thioredoxin,
a Heterologous Non-Collagenous Protein
P. Li, J.Y. Zhou, Y.Y. Zhou, C.D. Qian,
O. Li, H. Min and X.C. Wu
The coiled-coil neck domain of pulmonary surfactant protein
D (SP-D) is required for trimeric association and the subsequent
assembly of functional dodecamers of SP-D. It is also necessary
and sufficient for trimerization of a heterologous collagen
sequence. To investigate whether it is capable of driving
trimerization of heterologous non-collagenous proteins, we
expressed and purified a fusion of a heterologous non-collagenous
sequence (thioredoxin) to the coiled-coil neck domain of human
SP-D here. While western blot analysis detected a small population
of stable trimers of the fusion protein, chemical cross-linking
and SEC-HPLC indicated that the fusion protein was predominantly
a trimer. In contrast, purified thioredoxin without the fusion
was found only as monomers and dimers. We also measured the
thermal stabilities (with circular dichroism) and degradation
rates of these two proteins. Our data showed that the fusion
protein had a melting temperature that was 13 K higher than
that of thioredoxin and a longer degradation half life than
thioredoxin. Our findings indicate that the coiled-coil neck
domain of SP-D enables the trimerization and stabilization
of the heterologous non-collagenous thioredoxin. It may provide
new clues for further study on the application of this human
original coiled-coil domain in protein engineering to construst
trimeric functional fusion proteins.
[Back to top]
[Purchase
Article] [PMID:
19275747 PubMed - indexed for MEDLINE]
Total Synthesis of Cyclosporin O: Exploring the Utility
of Bsmoc-NMe-Amino Acid Fluorides and KOAt
V.V. Sureshbabu, S.J. Tantry, G. Chennakrishnareddy
and G. Nagendra
Cyclosporin O (CyO), an immunosuppressent cyclic undecapeptide,
was synthesized by convergent approach employing Bsmoc-Nmethyl
amino acid fluorides and Potassium Salt of 7-Aza-1-hydroxybenzotriazole
(KOAt) in solution by stepwise assembly. The couplings were
found to be epimerisation free. The difficulty in the coupling
of four consecutive N-methyl amino acids at position
8, 9, 10 and 11 was overcome by repeating the coupling thrice
at these critical positions. All the ten protected peptide
fragments of CyO starting from the dipeptide to the undecapeptide
and final protected as well as CyO were isolated and fully
characterized.
[Back to top]
[Purchase
Article] [PMID:
19275748 PubMed - indexed for MEDLINE]
Molecular Cloning of Grass Carp Growth Hormone Receptor
and Its Functional Interaction with Silver Carp Growth Hormone
W. Hu, X. Chen, G. Yu, Y. Chen, Y. Shen,
Y. Zhang and Y. Gong
A novel grass carp growth hormone receptor (gcGHR) cDNA
was cloned by RT-PCR method. CHO-K1 cells were transfected
with eukaryotic expression vector pcDNA3.0 containing gcGHR
entire coding region, resulting in a stable CHO cell line
expressing gcGHR (CHO-gcGHR). Bioactivity assay revealed that
silver carp growth hormone (scGH) bound gcGHR with dissociation
constant (Kd) value of 1.96
nM and stimulated CHO-gcGHR cells proliferation with the sensitivity
of 20 ng/ml. The cells proliferation assay was also provided
to measure fish growth hormone levels of pituitary and refolded
protein.
[Back to top]
[Purchase
Article] [PMID:
19275749 PubMed - indexed for MEDLINE]
Studies on the Acid Induced Unfolding of Human Serum
Albumin
P. Salahuddin
The acid induced unfolding of HSA (Human Serum Albumin)
was studied using UV-difference spectroscopy, fluorescence
spectroscopy and far-UV CD spectroscopy. In UV-difference
spectroscopy, the molar extinction coefficient decreased from
N state to F state. Partially buried Tyr residues are transferred
from a medium of high polarizability (native N state ) to
a medium of low polarizability (F state). This is followed
by loss of two electrostatic interactions Lys 205-Glu 465
and Arg218-Asp451 or one electrostatic interaction Lys205-Glu
465 / Arg218-Asp451 and one buried carboxyl group of acidic
amino acid. Similarly, UV-difference spectroscopy showed a
decrease in absorbance in F E
transition due to exposure of completely buried tyrosine residues
from medium of high polarizability (F state) to a medium of
low polarizability (E state). This is also followed by loss
of one electrostatic interaction out of three electrostatic
interactions namely, Asp187-Lys432, Asp187-Lys521 and Lys190-Glu425.
The tryptophanyl fluorescence spectra showed that the NF
transition is accompanied by a decrease in fluorescence intensity.
This implies that there is partial exposure of Trp214 to aqueous
environment. Consequently, there is a loss of two electrostatic
interactions Lys 205-Glu 465 and Arg218-Asp451 or one electrostatic
interaction Lys205-Glu 465 / Arg218-Asp451 and one buried
carboxyl group of acidic amino acid in NF
transition. The tryptophanyl fluorescence spectroscopy also
showed that partially exposed Trp214 residue becomes nearly
completely exposed in FE
transition. This is also followed by loss of two electrostatic
interactions out of three Asp 187-Lys432,Asp187-Arg521 and
Lys190-Glu425 in FE
transition. Taken together, these results showed that in NF
and FE
transitions a different number of electrostatic interaction
is detected by different techniques. Secondly, in both NF
and FE
transitions, chromophoric groups are exposed first to aqueous
environment and this is followed by loss of electrostatic
interactions.
[Back to top]
[Purchase
Article] [PMID:
19275750 PubMed - indexed for MEDLINE]
Crystallization and Preliminary X-Ray Analysis of
the Splice Variant of Human Ankyrin Repeat and Suppressor
of Cytokine Signaling Box Protein 9 (hASB9-2)
X. Fei, Y. Zhang, X. Gu, R. Qiu, Y. Mao
and C. Ji
Human ankyrin repeat and suppressor of cytokine signaling
box protein 9 (hASB9), a subunit of an Elongin C-cullin-SOCS
box (ECS) E3 ubiquitin ligase complex, is believed to be involved
in specific substrate-recognition for ubiquitination and degradation.
In fact, this specific substrate-recognition is determined
by the ankyrin repeats of hASB9 protein. Here, we have cloned
and overexpressed the hASB9-2, the splice variant of hASB9
with only one ankyrin repeat domain, as a 6His-tagged recombinant
protein in Escherichia coli. The purified hASB9-2
protein was crystallized by the hanging-drop vapor-diffusion
technique and diffracted to 2.2Å
resolution. The data showed that the cubic hASB9-2 crystal
belongs to space group P4332
with unit-cell parameters (a=b=c=129.25Å
α=β=γ=90º).
An asymmetric unit in the crystal was assumed to contain one
protein molecule giving the Matthews Coefficient factor of
2.81 and the solvent content of 56.3%.
[Back to top]
[Purchase
Article] [PMID:
19275751 PubMed - indexed for MEDLINE]
Crystallization and Preliminary X-Ray Crystallographic
Studies on SI-CLP, a Novel Human Glyco_18 Domain–Containing
Protein
G. Meng, X. Bai, T.J. Green, M. Luo and
X. Zheng
A novel human Glyco_18 domain–containing protein,
SI-CLP, was detected recently in human bronchoalveolar lavage
of patients with chronic inflammatory disorders of the respiratory
tract and peripheral-blood leukocytes. The expression of SI-CLP
is up-regulated by dexamethasone or IL-4 and involved in the
Th2 cell pathway. To further investigate its structure and
function will provide new insights into human immunity and
related disorders. Here we provide a preliminary crystal image
of SI-CLP using the hanging-drop vapor diffusion method. The
crystals of SI-CLP diffracted X-rays to a resolution of 2.7
Å.
The crystals belong to the space group P3221
with unit cell parameters a = b =99.79 Å,
c =250.53 Å,
α=β=900,
γ=1200.
There are two molecules per asymmetry unit.
[Back to top]
[Purchase
Article] [PMID:
19275752 PubMed - indexed for MEDLINE]
Crystallization and Preliminary Crystallographic
Analysis of Recombinant Human Calcyphosine
H. Dong, Z. Lou, X. Xu, D. Su, X. Zhou,
X. Li and M. Bartlam
Human calcyphosine was cloned into the pET-28a vector
and highly expressed in Escherichia coli BL21 (DE3)
cells. The protein was purified and crystallized. The crystal
diffracted to 2.8 Å
and belonged to space group P21212,
with the unit cell parameters a=70.39 Å,
b=132.02 Å,
c=46.20 Å.
|
