Protein & Peptide Letters, Volume 9, No. 2, 2002
Recent Advances in Atomic Resolution Protein Crystallography Pp.95-105
Luciana
Esposito, Luigi Vitagliano, Lelio Mazzarella
Recent Progress on Collagen Triple Helix
Structure, Stability and Assembly Pp.107-116
Rita
Berisio, Luigi Vitagliano, Lelio Mazzarella, Adriana Zagari
Atomic Force Microscopy and Proteins Pp.117-125
Luciano
Paulino da Silva
Structure/Function Relationships within the
Rna Recognition Motif Family Applied to the Hermes
Gene Product Pp.127-132
Laurent
Thion and Monique Erard
Presence of Distinct Virtual Backbone Torsion
Angles in Dipeptide Conformers
Pp.133-138
Gupta
S., Grail B. M., Payne J.W.
Study on Interaction between Duodenase –
Protease with Dual Specificity and Inhibitors of Bowman-Birk Family Pp.139-144
Inna
P. Gladysheva, Natalia A. Popykina, Tatyana S. Zamolodchikova and Natalia I.
Larionova
Homodimerization of Human Mu-Opoid Receptor
Overexpressed in Sf9 Insect Cells Pp.145-152
Chen
Li-Wei, Gao Can, Zhou De-He, Wei Qiang, Xu Xue-Jun, Chen Jie, and Chi Zhi-Qiang
Molecular Modeling of Transmembrane Helices 6
and 7 of the Heptahelical Lutropin Receptor Pp.153-158
J.
Paul Simon, Krassimira Angelova, and David Puett
Purification and Characterization of a New
Lectin from the Red Marine Alga Hypnea Musciformis Pp.159-165
C.S.Nagano,F.B.M.B.Moreno,C.BlochJr,M.V.Prates,J.J.Calvete,S.SakerSampaio,W.R.L.Farias,T.D.Tavares,
K.S.Nascimento,T.B. Grangeiro, B.S. Cavada,A.H.Sampaio
Flexible Crosslinked Benzhydryl Support for
Gel-Phase Peptide Synthesis
Pp.167-172
I.M.
Krishna Kumar & Beena Mathew
The Effect of Fibrillar Aβ1-40 on
Membrane Fluidity and Permeability Pp.173-178
Xiaocui
Ma, Yinlin Sha, Kechun Lin, Songqing Nie
Topographical Analysis of Schizolobium Parahyba
Chymotrypsin Inhibitor (Spci) By Atomic
Force Microscopy Pp.179-184
José Roberto S. A. Leite, Luciano Paulino Silva, Clarice Cunha Taveira, Rozeni C. L. Teles, Sonia M. de Freitas and Ricardo Bentes Azevedo
[Back to top] Recent Advances in Atomic Resolution Protein Crystallography
Luciana Esposito, Luigi Vitagliano, Lelio Mazzarella
In the search for increasingly
accurate protein structures, technological advances are opening up new
possibilities. In the last few years the wide accessibility of intense
synchrotron sources, the availability of efficient 2D-detectors, and the
routine use of cryo-crystallography techniques have yielded a significant
number of atomic resolution protein structures. Here we review the most
interesting results achieved in this field with a particular emphasis to the
biological implications and to the correlation between protein geometry and
conformation.
[Back to top] Recent Progress on Collagen Triple Helix
Structure, Stability and Assembly
Rita Berisio, Luigi Vitagliano, Lelio Mazzarella, Adriana Zagari
Collagen is the major structural protein in skin, bone, tendon, cartilage and blood vessels. Its triple helical structure has been long studied by fibre diffraction. More recently, single crystal X-ray diffraction on collagen-like polypeptide models has allowed a significantly improved description of the triple helix and it has shed light on the relationships between triple helix features and stability. This review outlines the current knowledge regarding collagen triple helix structure, stability, and assembly, with a particular emphasis on the latest structural results.
[Back to top] Atomic Force Microscopy and Proteins
Luciano Paulino da Silva
This review
briefly introduces the principles of atomic force microscopy (AFM) applied to
protein samples. AFM provides three-dimensional surface images of the proteins
with high resolution. The advantage of AFM for protein studies is that AFM can
visualize directly the molecule under physiological conditions without previous
treatment. AFM operated in the force-spectroscopy mode is now a widespread
technique, often used to investigate ligand–receptor interactions with the goal
of measuring forces at the individual molecule level.
[Back to top]
Structure/Function Relationships within the Rna Recognition
Motif Family Applied to
the Hermes Gene Product
Laurent Thion and Monique Erard
The RNA
Recognition Motif (RRM) family of RNA-binding domains comprises distinct
structural subclasses which can be equated to various types of cognate RNAs in
relation to biological functions. By identifying structural templates within
the appropriate RRM subclass, we have homology-modelled the three-dimensional
structure of the hermes gene-encoded RRM. Our findings lead us to propose
potential RNA targets for the corresponding protein and to predict possible
functions in RNA metabolism during heart development.
[Back to top] Presence of Distinct Virtual Backbone Torsion
Angles in Dipeptide Conformers
Gupta S., Grail B. M., Payne J.W.
Zwitterionic
dipeptides have recently been shown to exist in water mainly as nine
conformational forms with specific combinations of backbone y, w and f torsions, which allows conformer-specific molecular
recognition of peptide ligands by proteins. Here, we show that pairs of virtual
backbone torsions can also define these nine conformational forms, and that
comparing these virtual torsions in dipeptides with those of backbone-modified
pseudopeptides offers an improved procedure for evaluating peptidomimetics for
therapeutic applications.
[Back to top] Study on Interaction Between Duodenase –
Protease with Dual Specificity and Inhibitors of Bowman-Birk Family
Inna
P. Gladysheva, Natalia A. Popykina, Tatyana S. Zamolodchikova and Natalia I.
Larionova
The interaction
between duodenase and inhibitors of Bowman-Birk type from soybeans (BBI) and
lima beans (LBI) was investigated. Duodenase was shown to interact only with
antichymotrypsin site of these inhibitors. The inhibition constants of
duodenase by BBI, LBI, BBI-trypsin and LBI trypsin complexes were 4, 23, 400,
600 nM respectively.
[Back to top] Homodimerization of Human Mu-Opoid Receptor
Overexpressed in Sf9 Insect Cells
Chen Li-Wei, Gao Can, Zhou De-He, Wei Qiang, Xu
Xue-Jun, Chen Jie, and Chi Zhi-Qiang
In this study, we
demonstrate that human mu-opioid receptors do form SDS-resistant homodimers and
examine the ability of human mu-opioid receptors to dimerize and the role of
agonists in the dimerization. Increasing concentrations and longer exposure of
agonists reduce the levels of dimmer with a corresponding increase in the
levels of monomer. This effect is achieved with both peptide and alkaloid
opioid agonists and it is antagonist reversible. These results suggest that
human mu-opioid receptors are present as receptor oligomers and interconversion
between dimeric and monomeric forms may be important for biological activity.
[Back to top] Molecular Modeling of Transmembrane Helices 6
And 7 of the Heptahelical
Lutropin Receptor
J. Paul Simon, Krassimira Angelova, and David Puett
In response to
ligand binding and activating mutations, the lutropin receptor undergoes a
conformational change to trigger a cellular response. D556 is the most common
locus for naturally occurring activating mutations of the lutropin receptor,
and a D556A mutant is shown to be constitutively active. A water-mediated proton transfer is
postulated as part of the transmembrane signaling mechanism. Using energy minimization and ab initio
calculations, a hydrogen bonding network involving a highly constrained water
molecule(s) and D556 (helix 6) and N593/N597/Y601 (helix 7) is presented.
[Back to top] Purification and Characterization of a New
Lectin from the Red Marine Alga Hypnea Musciformis
C.S.Nagano,F.B.M.B.Moreno,C.BlochJr,M.V.Prates,J.J.Calvete,S.SakerSampaio,W.R.L.Farias,T.D.Tavares,
K.S.Nascimento,T.B. Grangeiro, B.S. Cavada,A.H.Sampaio
A lectin from the
red marine alga Hypnea musciformis (HML) was purified by extraction with 20 mM
PBS, precipitation with 70% saturated ammonium sulphate, ion-exchange
DEAE-Cellulose chromatography and RP-HPLC. The 9.3 kDa polypeptide agglutinates
erythrocytes from various sources and shows oligomerization tendencies under
certain MALDI-TOF/MS conditions. Preliminary N-terminal sequencing and
biological assays strongly suggest that the HML may belong to a new class of
algae lectins.
[Back to top] Flexible Crosslinked Benzhydryl Support for
Gel-Phase Peptide Synthesis
I.M. Krishna Kumar & Beena Mathew
An amphiphilic
support was developed by the suspension polymerization of styrene and
1,4-butanediol dimethacrylate. The
copolymer was converted to benzhydryl
resin, BDDMA-PS-BH, by a two-step polymer analogous reaction. This resin was employed as a support for the
synthesis of delta sleep inducing peptide (DSIP), Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu, in high yield and
purity by Fmoc / t-Bu tactics.
[Back to top] The Effect of Fibrillar Aβ1-40 on
Membrane Fluidity and Permeability
Xiaocui Ma, Yinlin Sha, Kechun Lin, Songqing Nie
The time course of
Aβ fibril formation was characterized using a variety of assays. The
effect of Aβ on the membrane fluidity and permeability was assessed by
monitoring the anisotropy of the fluorescent probe DPH and TMA-DPH and
measuring the release of vesicle-entrapped with three different molecular
weight fluorescence probes (ANTS/DPX, Calcein, FD-4). The results show fibrils
had formed after 4 days. Aggregated Aβmay decrease the membrane fluidity
and induce the leakage of ANTS and Calcein in a dose –dependent manner. These
effects may have some relation with Aβneurotoxicity.
[Back to top] Topographical Analysis of Schizolobium Parahyba Chymotrypsin inhibitor (Spci) by Atomic Force Microscopy
José Roberto S. A. Leite, Luciano Paulino Silva,
Clarice Cunha Taveira, Rozeni C. L. Teles, Sonia M. de Freitas and Ricardo
Bentes Azevedo
Atomic Force
Microscopy (AFM) has been a useful tool for molecular surface analysis and to
estimate topographical properties of proteins. Here we report a topographical
study of a chymotrypsin inhibitor from Schizolobium parahyba seeds (SPCI) by
AFM. The underlying structure of SPCI oligomers has been resolved in nanometer
order resolution. SPCI oligomerize in hexagonal, ellipsoid, comet, pyramidal,
and "Z" shaped. The hexagonal was the most observed oligomer shape.