Crystal Structure of
Trichosanthes kirilowii Lectin- 1 and Its Relation to the Type 2 Ribosome
Inactivating Proteins. Pp.
81-87
Effects of Increased Loop Flexibility
on the Structure and Stability of a De Novo Designed Helical
Protein. Pp. 89-96
Expression of Recombinant
Hepatitis B Virus Antigen HBsAg In Transgenic Plant Callus Pp. 97-100
Effect of the pH In the
Conformation and Activity of the Acid Protease from Aspergillus saitoi Pp.
101-108
Comparison
of Defense Responses Between Potato Cultivars Susceptible and Resistant to
Andean Potato Mottle Virus Pp. 109-114
Occurrence Of a Repeating Il-Mer
Amino Acid Sequence Motif in Diverse Organisms Pp. 115-122
Triazine Conjugates for
Multiple Site-Specific Labeling of Peptides Pp. 123-129
Production, Purification, And
Biological Activity Analysis of
Recombinant Human Persephin Expressed in Insect Cells Pp. 131-138
Predicted Fold For The Abri
Amyloid Subunit: A Model For Amyloidogenesis In Familial British
Dementia Pp. 139-146
Synthesis and Biological
Effect of an Anorectic Peptide CART (Cocaine- and
Amphetamine-Regulatedtranscript) (Human55-102) Analogue Pp. 147-151
Syntheses of Cholecystokin
(CCK) Fragment Analogues (26-33) and Comparative Effect on Decreased Feeding in Rats By CCK Fragment (26-33) Pp.153-158
[Back to top] Crystal Structure of
Trichosanthes kirilowii Lectin- 1 and Its Relation to the Type 2 Ribosome
Inactivating Proteins.
Crystal structure of a two-chain
lectin, isolated from the tuber of Trichosanthes kirilowii, was solved by the
molecular replacement method using abrin-a as probe. From the present density
map at 2.7Å resolution, it could be seen that a residue corresponding to an
invariant tyrosine locating in the active site of ribosome-inactivating
proteins (RIPs) is replaced with a non-aromatic one. This may be the reason why
this kind of lectins has no RIPs' activity, even though they possess some
properties similar to type 2 RIPs).
[Back to
top] Effects of Increased
Loop Flexibility on the Structure and Stability of a De Novo Designed Helical
Protein.
MB-l is a de novo protein
designed to incorporate amino acids required for dairy cow nutrition while
folding into a four-helix-bundle. Analysis shows that, as per design, MB-l is a
largely helical protein but appears to be dimeric and shows less stability than
expected. Recent evidence indicates that the loop regions in MB-l may have been
under-designed. The variant, MB-16, described here attempts to correct
potentially detrimental effects on turn formation by introducing a flexible,
five-glycine residues sequence as the second loop.
[Back to
top] Expression of Recombinant Hepatitis B Virus Antigen HBsAg In
Transgenic Plant Callus
The coding sequence of the
surface antigen HBsAg of hepatitis B virus was cloned into a plant expression
vector under the control of cauliflower mosaic virus 35S promoter. Cotyledons,
hypocotyls and roots of lettuce cultivar "Vit6ria" were transformed
by cocultivation with Agrobacterium tumefaciens harbouring the recombinant
plasmid. Lettuce callus tissue grown on selective medium was analysed and the
presence of the transgene confirmed by PCR. Expression of recombinant protein
HBsAg was confirmed by Western Blot.
[Back to
top] Effect of the pH In
the Conformation and Activity of the Acid Protease from Aspergillus saitoi
The circular dichroism spectrum
in the far UV-region (190-240 nm) indicates that the acid protease from
Aspergillus saitoi contains appreciable amounts of b-sheet. The structure-activity relationship of the protein is
studied as a function of the pH.
.
[Back to
top] Comparison of Defense Responses Between Potato Cultivars
Susceptible and Resistant To Andean Potato Mottle Virus
Potato genotypes that differ in
their resistance to Andean Potato Mottle Virus (APMoV) were analyzed regarding
their response to stress induced by APMoV inoculation. Using 1- and 2-D
electrophoretic analysis, a substantial difference was observed between the
patterns of induced/reduced polypeptides in the leaves of susceptible plants
(cv. Delta) and resistant ones (cv. Bintje). Western blot analysis indicates
the presence of a virus-inducible chitinase in the susceptible cultivar.
[Back to
top] Occurrence Of a
Repeating Il-Mer Amino Acid Sequence Motif in Diverse
Organisms
A repeating Il-mer amino acid sequence motif; first recognized in plant seed proteins, has been observed in such diverse organisms as the nematode Caenorhabditis elegans and the eubacteria Haemophilus influenzae and Deinococcus radiodurans. Amino acid preferences at each position in the motif are presented, as are dot matrix sequence comparisons between several of the proteins harboring the repeating motif Although implicated in plant abiotic stress tolerance, no molecular function for the proteins carrying the motif has yet been uncovered.
[Back to
top] Triazine Conjugates
for Multiple Site-Specific Labeling of Peptides
Mono- and di-substituted
triazines were appended to the side chain of lysine or ornithine, which was
then used in the synthesis of peptides. In this way, environment-sensitive
"reporter" groups can be included in a sequence-specific manner in a
peptide. The triazine adducts are stable to standard conditions employed in
peptide synthesis. Several model peptides showing the utility of these
conjugates were prepared.
[Back to
top] Production,
Purification, And Biological Activity
Analysis of Recombinant Human Persephin Expressed in Insect Cells
Zhe-Yu Chen Xing-Dong Zheng, Li Cao, Chang-Lin Lu,
Xiang-Fu Wu and Cheng He
Recombinant human Persephin (PSP)
has been expressed at high levels in recombinant baculovirus infected
Trichoplusia ni (Tn-5Bl-4) cells. The expressed protein was purified by nickel
affinity chromatography. Pure, recombinant human PSP promoted the survival of
embryonic motor neurons in vitro but failed to protect adult rat spinal cord
motor neurons after sciatic nerve transection in vivo. Because recombinant
bioactive human PSP can be obtained in large quantities, and purified to near
homogeneity, they are suitable for further biological activity investigation.
[Back to top] Predicted Fold For The Abri Amyloid Subunit: A Model For Amyloidogenesis In Familial British Dementia
ABri is a 34 residue polypeptide
that forms amyloid fibrils in Familial British Dementia (FED). A PSI-Blast
search, 3 different fold recognition programs and 3D model-building indicated
that it has 3 b-strands forming an
antiparallel b-sheet and a small
C-terminal a-helix. In order to
validate the prediction, the region coding the Abri polypeptide was cloned,
expressed and purified from E.Coli. Circular Dichroism (CD) spectroscopy of
ABri in aqueous solution shows it to have a predominantly b-sheet structure with a small a-helical component.
[Back to
top] Synthesis and
Biological Effect of an Anorectic Peptide CART (Cocaine- and Amphetamine-Regulatedtranscript)
(Human55-102) Analogue
[Phe(4F)97]CART55-102
was synthesized by a solid-phase method. Hydrogen fluoride was used to
deprotect and cleave the peptide from the resin except for Acm groups and a
Met(0) residue. The product was treated with dithiothreitol to remove a
sulfoxide group of Met(0) residue and then treated with Hg(OAc)2 in
50% aqueous AcOH to remove Acm groups. The reduced peptide was subjected to
oxidative folding to form disulfide bridges. The crude product was purified by
PR-HPLC. The synthetic [Phe(4F)97CART55-102 and CART55-102 were
tested for comparative effect on inhibitory food intake in rats. This peptide
exhibited far stronger inhibitory effect than that of the synthetic CART55-102
[Back to
top] Syntheses of
Cholecystokin (CCK) Fragment Analogues (26-33) and Comparative Effect on
Decreased Feeding in Rats By CCK
Fragment (26-33)
The peptide analogues of cholecystokinin (CCK) fragment 26-33 in which phenylalanin residue at the33th position are replaced by phenyl glycine [Phg], 1-naphthylalanine [1-Nal], 4-f1uorophenylalanine [Phe(4F)], cyclohexylalanine [cHex] and O-methyltyrosine [Tyr(Me)]], were synthesized by a solid-phase method and the feeding significance of the aromatic amino acid of this position was comparatively investigated. The in vivo comparative effect on the decreased feeding in rats by peripherally CCK-8 was tested. The observed activities of these peptides were in order [Phe(4F)33]CCK-8>[1-Nal33]CCK-8>CCK-8>[Tyr(Me)33]CCK-8>[Phg33]CCK-8. However, the one analogue, [cHex33]CCK-8, had no inhibitory effect on food intake in rats.