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1.
Hatzizisis D Gaitanaki C Beis I 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(5-6):447-456
The effects of a calpain-like proteinase (CaDP) isolated from the arm muscle of Octopus vulgaris on the myofibrils and myofibrillar proteins isolated from the same tissue were examined. Our studies clearly showed that
treatment of intact myofibrils with CaDP in the presence of 5 mM Ca2+ results in the degradation of the major myofibrillar proteins myosin, paramyosin, and actin. From the isolated α- and β-paramyosins
only β-paramyosin is degraded by CaDP in the presence of 5 mM Ca2+ producing three groups of polypeptides of 80, 75, and 60 kDa, respectively. The degradation rate depends on the proteinase
to substrate ratio, temperature, and time of proteolysis and is inhibited by the endogenous CaDP inhibitory factor (CIF),
as well as by various known cysteine proteinase inhibitors (E-64, leupeptin, and antipain). From the other myofibrillar proteins
examined myosin, but not actin, is degraded by CaDP; myosin heavy chain (MHC, 200 kDa) is degraded by CaDP producing four
groups of polypeptides of lower molecular masses (155, 125, 115, and 102 kDa, respectively); the degradation rate depends
on the incubation time and the proteinase to substrate ratio. Furthermore, CaDP undergoes limited autolysis in the presence
of both the exogenous casein and the endogenous β-paramyosin producing two large active fragments of 52 and 50.6 kDa, respectively;
CIF reversibly inhibits this CaDP autolysis.
Accepted: 26 May 2000 相似文献
2.
Proteolytic cleavage of plant proteins by peroxisomal endoproteases from senescent pea leaves 总被引:13,自引:0,他引:13
The degradation of peroxisomal and nonperoxisomal proteins by endoproteases of purified peroxisomes from senescent pea (Pisum sativum L.) leaves has been investigated. In our experimental conditions, most peroxisomal proteins were endoproteolytically degraded.
This cleavage was prevented, to some extent, by incubation with 2 mM phenylmethylsulfonylfluoride, an inhibitor of serine
proteinases. The peroxisomal enzymes glycolate oxidase (EC 1.1.3.1), catalase (EC 1.11.1.6) and glucose-6-phosphate dehydrogenase
(EC 1.1.1.49) were susceptible to proteolytic degradation by peroxisomal endoproteases, whereas peroxisomal manganese superoxide
dismutase (EC 1.15.1.1) was not. Ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39) from spinach and urease (EC
3.5.1.5) from jack bean were strongly degraded in the presence of peroxisomal matrices. These results indicate that proteases
from plant peroxisomes might play an important role in the turnover of peroxisomal proteins during senescence, as well as
in the turnover of proteins located in other cell compartments during advanced stages of senescence. On the other hand, our
data show that peroxisomal endoproteases could potentially carry out the partial proteolysis which results in the irreversible
conversion of xanthine dehydrogenase into the superoxide-generating xanthine oxidase (EC 1.1.3.22). This suggests a possible
involvement of the peroxisomal endoproteases in a regulated modification of proteins.
Received: 25 January 1999 / Accepted: 3 June 1999 相似文献
3.
Proteins in yeast growing in a medium with glucose or ethanol as carbon source were pulse-labelled by a 20-min incubation
with14C-leucine. The proteins in cells labelled and growing in a glucose medium were stable; when this population was transferred
to the ethanol medium, the proteins were degraded at a rate of 1.1 %/h. The population labelled and growing in an ethanol
medium displayed a fraction of short-lived proteins (about 4 %), decaying with a half-life of 0.5 h. The size of the short-lived
protein fraction increased slightly after shifts to a glucose as well as to a starvation medium. The residual long-lived proteins
underwent a turnover of 1.3 –1.4 %/h in the ethanol or the starvation medium and of 0.3 %/h in the glucose medium, respectively.
Proteins labelled in the presence of canavanine or ethionine were degraded at only a slightly greater rate than the normal
proteins.
Participant of the UNESCO Postgraduate Course “On Modern Problems in Biology”. 相似文献
4.
Degradation of abnormal proteins in Bacillus megaterium and Saccharomyces cerevisiae in vivo was compared with that in cell-free extracts. Protein degradation in vivo, when the cells were labelled with 14C-leucine during growth in the presence of ethionine, was affected by the concentration of the analogue used. Proteins synthesized in the presence of 0.2–1 mM ethionine were degraded most rapidly in both organisms. The proteolytic enzyme system of yeast degraded the analogue-containing proteins in vitro faster than the normal proteins. This holds also for proteins synthesized in the presence of 5 mM ethionine, whose degradation in vivo was impaired. The proteolytic system of B. megaterium, on the other hand, was unable in vitro to differentiate between normal and abnormal proteins. Denatured proteins underwent preferential degradation over normal and ethionine-containing proteins.Participant in the UNESCO Postgraduate Course On Modern Problems in Biology and Microbial Technology. 相似文献
5.
Degradation of normal as well as canavanine proteins in growing yeast is suppressed by glucose. This suggests that the same
mechanism may be operating in the catabolism in both cases. Degradation of normal and canavanine proteins is increased by
disintegration of cell structure. Proteins synthesized in the presence of an amino acid analogue may not be degraded preferentiallyin vivo even when they are rather sensitive to endogenous proteolytic enzymes.
Participant of the UNESCO postgraduate course onModern Problems in Biology. 相似文献
6.
Considerable advances in the research field of erythrocyte membrane were achieved in the recent two decades. New findings
in the structure-function correlation and interactions of erythrocyte membrane proteins have attracted extensive attention.
Interesting progress was also made in the molecular pathogenesis of erythrocyte membrane disorders. Advances in the composition,
function and interaction of erythrocyte membrane proteins, erythrocyte membrane skeleton, and relevant diseases are briefly
described and summarized here on the basis of domestic and world literatures.
Translated from Life Science Research, 2005, 9(4): 283–291 [译自: 生命科学研究] 相似文献
7.
Willy J. Peumans Koen Smeets Karel Van Nerum Fred Van Leuven Els J. M. Van Damme 《Planta》1997,201(3):298-302
Analysis of nectar from leek (Allium porrum) flowers by SDS-PAGE revealed the presence of two major polypeptide bands of 50 kDa and 13 kDa, respectively. Using a combination
of agglutination tests, enzyme assays and N-terminal sequencing, the polypeptides have been identified as subunits of alliin
lyase (alliinase, EC 4.4.1.4) and mannose-binding lectin, respectively. The latter protein is particularly abundant since
it represents about 75% of the total nectar protein. Honey produced by bees foraging on flowering leek plants still contains
biologically active lectin and alliinase. However, the levels of both proteins are strongly reduced as compared to those in
the original nectar. It is evident, therefore, that the lectin as well as the alliinase are inactivated/degraded during the
conversion of nectar into honey.
Received: 24 May 1996 / Accepted: 19 August 1996 相似文献
8.
Synthetic genes were designed to encode analogs of the two proteins of Nephila clavipes dragline silk, spidroins 1 and 2. The genes were constructed of tandem repeats of relatively long (more than 300 bp) DNA
sequences assembled from synthetic oligonucleotides, and encoded proteins of high molecular mass (65–163 kDa). Both analogs
were produced efficiently in Escherichia coli. The yield and homogeneity of the products of longer genes were limited by premature termination of synthesis, probably as
a result of processivity errors in protein synthesis. Average termination rates were determined to be 1 in 1100 codons to
1 in 300 codons, depending on the length and synonymous codon choices of the gene. Both analog proteins could be induced to
form stable aqueous solutions without denaturants. Circular dichroism spectra of the purified proteins in dilute solution
resembled spectra of redissolved natural dragline silk in reflecting a largely disordered structure in water and more ordered
structures in mixed solvents with methanol and trifluoroethanol.
Received: 4 March 1996 / Received revision: 29 July 1996 / Accepted: 12 August 1996 相似文献
9.
The covalent modification of cell surface proteins with N-hydroxysuccinimide esters of biotin was used to develop a strategy for following the turnover of proteins on the surface
of carrot (Daucus carota L.) protoplasts. A biotinylation/internalisation assay was established which enabled the turnover of cell surface proteins
to be examined by biochemical and immunocytochemical techniques. The detection of biotinylated proteins after sodium dodecyl
sulfate-polyacrylamide gel electrophoresis and Western blotting indicated that a variety of proteins on the surface of the
protoplasts were covalently modified. Immunolocalisation of biotinylated proteins in protoplasts directly after their derivatisation,
demonstrated that the proteins were initially restricted to the cell surface. Incubation of biotinylated protoplasts at 25 °C
for 1 h resulted in the detection of biotin-labelled proteins on the cell surface and intracellularly. A small proportion
of these proteins was associated with coated pits, the Golgi apparatus and vacuolar compartments. Biochemical analysis of
internalised proteins revealed that a polypeptide of approximate Mr 100 000 was internalised by the protoplasts. Immunolabelling of a biotinylated protein of Mr 100 000 by an antibody raised against an isoform of a tobacco plasma-membrane H+-ATPase, strongly suggests that the plasma-membrane H+-ATPase is internalised by carrot protoplasts. The implications of these results are discussed within the context of endocytosis
in plants.
Received: 13 July 1998 / Accepted: 11 November 1998 相似文献
10.
Total proteins in the pollen of Humulus scandens Lour, one of the most popular aeroallergens in China, were analyzed by two-dimensional electrophoresis in the current study.
The proteins were extracted by Trichloracetic acid (TCA) method, and then separated by isoelectric focusing as the first dimension
and SDS-PAGE as the second dimension. The spots of proteins were visualized by staining with Coomassie Brilliant Blue. After
analysis with software (ImageMaster 2D), 122 different proteins were detected; isoelectric point (pI), Molecular weight (MW)
and relative volume of each protein in the pollen were also discovered. This is the first high-resolution, two-dimensional
protein map of the pollen of Humulus scandens Lour in China. Our finding has built a solid foundation for identification, characterization, gene cloning and standardization
of allergenic proteins in the pollen of Humulus scandens Lour for further studies.
Translated from Journal of Wuhan Botanical Research, 2006, 24(1): 58–62 [译自: 武汉植物研究] 相似文献
11.
Szyszka R 《Folia microbiologica》1999,44(2):142-152
Phosphorylation of ribosomal acidic proteins ofSaccharomyces cerevisiae is an important mechanism regulating a number of active ribosomes. The key role in the regulatory mechanism is played by
specific phosphoprotein kinases and phosphoprotein phosphatases. Three different cAMP-independent protein kinases phosphorylating
acidic ribosomal proteins have been identified and characterized. The protein kinase 60S (PK60S), RAP kinase, and casein kinase
type 2 (CK2). All three protein kinases phosphorylate serine residues which are localized in the C-terminal end of phosphoproteins.
Synthetic peptides were used to determinate the amino acid sequence of phosphoacceptor site for PK60S. Peptide AAEESDDD derived
from phosphoproteins YP1β/β′ and YP2α turned out to be the best substrate for PK60S. A number of halogenated benzimidazoles
and 2-azabenzimidazoles were tested as inhibitors of the three protein kinases. 4,5,6,7-Tetrabromo-2-azabenzimidazole inhibits
phosphorylation only of these polypeptides phosphorylated by protein kinase 60S, namely YP1β/β′ and YP2α, but not the other,
YP1α and YP2β phosphorylated by protein kinases RAP and CK2. RAP kinase has been found in an active form in the soluble fraction
ofS. cerevisiae. The enzyme uses ATP as a phosphate donor and is less sensitive to heparin than casein kinase 2. RAP kinase monophosphorylates
the four acidic proteins. The ribosome-bound proteins are a better substrate for the enzyme. Multifunctional CK2 kinase phosphorylate
all four acidic proteins. The kinase phosphorylates preferentially serine or threonine residues surrounded by cluster of acidic
residues. The enzyme activity is stimulatedin vitro by the presence of polylysine and inhibited by heparin.
Presented at theSymposium on Regulation of Translation of Genetic Information by Protein Phosphorylation, 21 st Congress of the Czechoslovak
Society for Microbiology, Hradec Králové (Czech Republic), September 6–10, 1998. 相似文献
12.
Evidence for graft transmission of structural phloem proteins or their precursors in heterografts of Cucurbitaceae 总被引:9,自引:0,他引:9
Interspecific and intergeneric grafts of Cucurbitaceae were used to study the mobility of structural P-proteins in the phloem.
When Cucumis sativus L. scions were grafted onto Cucurbita rootstocks, at least nine additional proteins appeared on sodium dodecyl sulfate-polyacrylamide electrophoresis gels of scion
exudate, 9–11 d after grafting. These proteins corresponded exactly to those of the respective Cucurbita sp. rootstock, including the filament-forming phloem protein PP1 and the phloem lectin PP2, as shown by the apparent molecular
weights and peptide maps. According to probing at three sites, the additional proteins were evenly distributed within the
scion. The appearance of additional proteins was correlated with the establishment of phloem bridges across the graft union.
The developmental coincidence establishes that the structural proteins or their precursors are translocated in the phloem.
This translocation was a universal phenomenon in Cucurbitaceae as shown by a comparative screening for additional proteins
in eleven graft combinations, using Benincasa hispida (Thunb.) Cogn., Citrullus colocynthis (L.) Schrad., Cucumis melo L, C. sativus, Cucurbita ficifolia Bouché, Cucurbita maxima Duchesne ex Lam., and Trichosanthes cucumerina var. lobata Roxb. According to this screening, the direction of transmission of additional proteins depended upon the combination tested.
While some graft partners failed to show exchange, some behaved as “donor” for additional proteins and still others could
be both “donor” or “acceptor”. However, whether used as scion or stock, C. sativus was consistently identified as an acceptor. The occurrence of additional proteins in heterografts is discussed with regard
to the transport mechanism of structural P-proteins in the phloem and its relationship to assimilate transport.
Received: 18 February 1998 / Accepted: 12 May 1998 相似文献
13.
The second messenger 3′–5′-cyclic diguanylic acid (c-di-GMP) promotes biofilm formation, and c-di-GMP is synthesized by diguanylate
cyclases (characterized by a GGDEF domain) and degraded by phosphodiesterases. Here, we evaluated the effect of the 12 E. coli GGDEF-only proteins on biofilm formation and motility. Deletions of the genes encoding the GGDEF proteins YeaI, YedQ, YfiN,
YeaJ, and YneF increased swimming motility as expected for strains with reduced c-di-GMP. Alanine substitution in the EGEVF
motif of YeaI abolished its impact on swimming motility. In addition, extracellular DNA (eDNA) was increased as expected for
the deletions of yeaI (tenfold), yedQ (1.8-fold), and yfiN (3.2-fold). As a result of the significantly enhanced motility, but contrary to current models of decreased biofilm formation
with decreased diguanylate cyclase activity, early biofilm formation increased dramatically for the deletions of yeaI (30-fold), yedQ (12-fold), and yfiN (18-fold). Our results indicate that YeaI, YedQ, and YfiN are active diguanylate cyclases that reduce motility, eDNA, and
early biofilm formation and contrary to the current paradigm, the results indicate that c-di-GMP levels should be reduced,
not increased, for initial biofilm formation so c-di-GMP levels must be regulated in a temporal fashion in biofilms. 相似文献
14.
15.
Acute-phase response is documented to be a significant mechanism of innate immunity in vertebrates and invertebrates. In this
study, proteomic methodologies were applied for different protein expressions in hemolymph of Scylla serrata challenged by Vibrio parahaemolyticus after immunization, and in muscles of the crabs separately challenged by V. parahaemolyticus, V. anguillarum and Aeromonas hydrophila. Up-regulated cryptocyanin is documented in the hemolymph and up-regulated calexcitin, wingless (fragment) and tachykinin-related
peptide in the muscle as acute-phase proteins. All the four altered proteins were responsible for bacterial stress, but cryptocyanin
seemed to be a memory response protein against the challenge by a live bacterium after immunization of the live cells. These
up-regulated proteins can be indicative of an understanding of immunity of a crab.
__________
Translated from Journal of Xiamen University (Natural Science), 2005, 44(4): 559–562, 44(Sup.): 191–194 [译自: 厦门大学学报(自然科学版), 2005, 44(4): 559–562, 44(增刊): 191–194] 相似文献
16.
Sampo Mäntylahti Olli Aitio Maarit Hellman Perttu Permi 《Journal of biomolecular NMR》2010,47(3):171-181
We propose a new alpha proton detection based approach for the sequential assignment of natively unfolded proteins. The proposed
protocol superimposes on following features: HA-detection (1) enables assignment of natively unfolded proteins at any pH,
i.e., it is not sensitive to rapid chemical exchange undergoing in natively unfolded proteins even at moderately high pH.
(2) It allows straightforward assignment of proline-rich polypeptides without additional proline-customized experiments. (3)
It offers more streamlined and less ambiguous assignment based on solely intraresidual 15N(i)-13C′(i)-Hα(i) (or 15N(i)-13Cα(i)-Hα(i)) and sequential 15N(i + 1)-13C′(i)-Hα(i) (or 15N(i + 1)-13Cα(i)-Hα(i)) correlation experiments together with efficient use of chemical shifts of 15N and 13C′ nuclei, which show smaller dependence on residue type. We have tested the proposed protocol on two proteins, small globular
56-residue GB1, and highly disordered, proline-rich 47-residue fifth repeat of EspFU. Using the proposed approach, we were able to assign 90% of 1Hα, 13Cα, 13C′, 15N chemical shifts in EspFU. We reckon that the HA-detection based strategy will be very useful in the assignment of natively unfolded proline-rich proteins
or polypeptide chains. 相似文献
17.
Improved methods are described for the detection of G1P-binding proteins (G-proteins) in the protonema of mossFunaria hygrometrica and coleoptiles of corn(Zea mays) and sorghum(Sorghum vulgare). We optimized conditions for the transfer of proteins to nitrocellulose, production of high titer polyclonal anti-Gα (common)
antibodies and finally the detection of G-proteins by amplification. In addition to the α-subunit of heterotrimeric G-proteins
(M
r 41–43 kDa), a small molecular weight class (< 30 kDa) was also detected by anti-Gα (common) antibodies. An easy, reliable
and efficient filter assay is also described to quantify the toxin catalyzed ADP-ribosylation. The apparentK
m of the NAD has been determined to be approximately 1.5μM for the microsomal fraction of moss. Inclusion of G1P stimulated
ADP-ribosylation by 2–27-fold. One to three polypeptides representing the α-subunit of heterotrimeric G-proteins of (Mr 37–43 kDa) were ADP-ribosylated in all three plants. The anti-Gβ (C-terminus) antibody cross-reacted strongly with 39 and 34 kDa polypeptide in moss and corn respectively. By employing improved
methods two classes of G-proteins have been shown to be present in three plant species. 相似文献
18.
Escherichia coli BL21 (DE3) is commonly used for the overproduction of fusion proteins. Using this system, we recently reported the overproduction
of histidine-tagged mouse estrogen receptor (ER) α-ligand binding domain as an intact 30 kD protein and its inhibitory effect on the growth of bacteria. However, when GST-tagged
mouse ERα transactivation domain (TAD) was overproduced using this system, it showed no effect on the growth of bacteria but was specifically
degraded during its expression and purification. Here we report the expression of 47 kD GST-tagged mouse ERα-TAD protein, which was degraded partially and specifically into 46 and 43 kD fragments. This fusion protein was further degraded
into 37, 31, 29 and 26 kD fragments during its purification by affinity chromatography. Such specific degradation of GST-tagged
mouse ERα-TAD during its overproduction in E. coli and purification indicates the induction of specific protease and suggests the modification of expression system. 相似文献
19.
Marielle Merlino Philippe Leroy Christophe Chambon Gérard Branlard 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,118(7):1321-1337
Albumins and globulins of wheat endosperm represent 20% of total kernel protein. They are soluble proteins, mainly enzymes
and proteins involved in cell functions. Two-dimensional gel immobiline electrophoresis (2DE) (pH 4-7) × SDS-Page revealed
around 2,250 spots. Ninety percent of the spots were common between the very distantly related cultivars ‘Opata 85’ and ‘Synthetic
W7984’, the two parents of the International Triticeae Mapping Initiative (ITMI) progeny. ‘Opata’ had 130 specific spots while
‘Synthetic’ had 96. 2DE and image analysis of the soluble proteins present in 112 recombinant inbred lines of the F9-mapped
ITMI progeny enabled 120 unbiased segregating spots to be mapped on 21 wheat (Triticum aestivum L. em. Thell) chromosomes. After trypsic digestion, mapped spots were subjected to MALDI-Tof or tandem mass spectrometry for
protein identification by database mining. Among the ‘Opata’ and ‘Synthetic’ spots identified, many enzymes have already been
mapped in the barley and rice genomes. Multigene families of Heat Shock Proteins, beta-amylases, UDP-glucose pyrophosphorylases,
peroxydases and thioredoxins were successfully identified. Although other proteins remain to be identified, some differences
were found in the number of segregating proteins involved in response to stress: 11 proteins found in the modern selected
cultivar ‘Opata 85’ as compared to 4 in the new hexaploid `Synthetic W7984’. In addition, ‘Opata’ and ‘Synthetic’ differed
in the number of proteins involved in protein folding (2 and 10, respectively). The usefulness of the mapped enzymes for future
research on seed composition and characteristics is discussed.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献