Search results for "Protein Complex"
showing 10 items of 154 documents
Changes in the protein profile of Quercus ilex leaves in response to drought stress and recovery
2009
To characterize the molecular response of holm oak to drought stress and its capacity to recover 9-month-old Quercus ilex seedlings were subjected to three treatments for a 14-d period: (i) continuous watering to field capacity (control plants, W), (ii) no irrigation (drought treatment, D), and (iii) no irrigation for 7d followed by a watering period of 7d (recovery treatment, R). In drought plants, leaf water potential decreased from -0.72 (day 0) to -0.99MPa (day 7), and -1.50MPa (day 14). Shoot relative water content decreased from 49.3% (day 0) to 47.7% (day 7) and 40.8% (day 14). Photosystem II quantum yield decreased from 0.80 (day 0) to 0.72 (day 7) and 0.73 (day 14). Plants subjecte…
Human Hsp60 with Its Mitochondrial Import Signal Occurs in Solution as Heptamers and Tetradecamers Remarkably Stable over a Wide Range of Concentrati…
2014
It has been established that Hsp60 can accumulate in the cytosol in various pathological conditions, including cancer and chronic inflammatory diseases. Part or all of the cytosolic Hsp60 could be naive, namely, bear the mitochondrial import signal (MIS), but neither the structure nor the in solution oligomeric organization of this cytosolic molecule has still been elucidated. Here we present a detailed study of the structure and self-organization of naive cytosolic Hsp60 in solution. Results were obtained by different biophysical methods (light and X ray scattering, single molecule spectroscopy and hydrodynamics) that all together allowed us to assay a wide range of concentrations of Hsp60…
Insertion of light-harvesting chlorophyll a/b protein into the thylakoid
2000
The major light-harvesting chlorophyll a/b-binding protein (Lhcb1,2) of photosystem II is inserted into the thylakoid via the signal recognition particle dependent pathway. However, the mechanism by which the protein enters the membrane is at this time unknown. In order to define some topographical restrictions for this process, we constructed several recombinant derivatives of Lhcb1 carrying hexahistidine tags at either protein terminus or in the stromal loop domain. Additionally, green fluorescent protein (GFP) was fused to either terminus. None of the modifications significantly impair the pigment-binding properties of the protein in the in vitro reconstitution of LHCII. With the excepti…
Predictive First-Principles Modeling of a Photosynthetic Antenna Protein: The Fenna–Matthews–Olson Complex
2020
High efficiency of light harvesting in photosynthetic pigment–protein complexes is governed by evolutionary-perfected protein-assisted tuning of individual pigment properties and interpigment interactions. Due to the large number of spectrally overlapping pigments in a typical photosynthetic complex, experimental methods often fail to unambiguously identify individual chromophore properties. Here, we report a first-principles-based modeling protocol capable of predicting properties of pigments in protein environment to a high precision. The technique was applied to successfully uncover electronic properties of the Fenna–Matthews–Olson (FMO) pigment–protein complex. Each of the three subunit…
Bio serves nano: biological light-harvesting complex as energy donor for semiconductor quantum dots.
2012
Light-harvesting complex (LHCII) of the photosynthetic apparatus in plants is attached to type-II core-shell CdTe/CdSe/ZnS nanocrystals (quantum dots, QD) exhibiting an absorption band at 710 nm and carrying a dihydrolipoic acid coating for water solubility. LHCII stays functional upon binding to the QD surface and enhances the light utilization of the QDs significantly, similar to its light-harvesting function in photosynthesis. Electronic excitation energy transfer of about 50% efficiency is shown by donor (LHCII) fluorescence quenching as well as sensitized acceptor (QD) emission and corroborated by time-resolved fluorescence measurements. The energy transfer efficiency is commensurable …
Kinetics of Insulin Aggregation: Disentanglement of Amyloid Fibrillation from Large-Size Cluster Formation
2006
Kinetics of human insulin aggregation has been studied at pH 1.6 and 60 degrees C, when amyloid fibrils are formed. We developed a novel approach based on the analysis of scattered light intensity distribution, which allows distinguishing between small and large size aggregates. By this method, we observed an exponential growth of fibrillar aggregates implying a heterogeneous aggregation mechanism. Also, the apparent lag time observed, correlated with the major increase of thioflavin T fluorescence, has been assigned to the onset of large size cluster formation.
The landscape of epilepsy-related GATOR1 variants
2019
Purpose:\ud \ud To define the phenotypic and mutational spectrum of epilepsies related to DEPDC5, NPRL2 and NPRL3 genes encoding the GATOR1 complex, a negative regulator of the mTORC1 pathway.\ud \ud Methods:\ud \ud We analyzed clinical and genetic data of 73 novel probands (familial and sporadic) with epilepsy-related variants in GATOR1-encoding genes and proposed new guidelines for clinical interpretation of GATOR1 variants.\ud \ud Results:\ud \ud The GATOR1 seizure phenotype consisted mostly in focal seizures (e.g., hypermotor or frontal lobe seizures in 50%), with a mean age at onset of 4.4 years, often sleep-related and drug-resistant (54%), and associated with focal cortical dysplasia…
Dense Bodies of a gH/gL/UL128/UL130/UL131 Pentamer-Repaired Towne Strain of Human Cytomegalovirus Induce an Enhanced Neutralizing Antibody Response
2019
The development of a vaccine against human cytomegalovirus infection (HCMV) is a high-priority medical goal. The viral pentameric protein complex consisting of glycoprotein H (gH)/gL/UL128-131A (PC) is considered to be an important vaccine component. Its relevance to the induction of a protective antibody response is, however, still a matter of debate. We addressed this issue by using subviral dense bodies (DBs) of HCMV. DBs are exceptionally immunogenic. Laboratory HCMV strain DBs harbor important neutralizing antibody targets, like the glycoproteins B, H, L, M, and N, but they are devoid of the PC. To be able to directly compare the impact of the PC on the levels of neutralizing antibody …
Purification of a glucose-binding protein from rat liver nuclei. Evidence for a role in targeting of nuclear mRNP to nuclear pore complex.
1992
A nuclear carbohydrate-binding protein with a molecular mass of 67 kDa (CBP67), which is specific for glucose residues, was purified to essential homogeneity from rat liver nuclear extracts. This protein could also be isolated from nuclear ribonucleoprotein (RNP) complexes by extraction in the presence of 0.6 M or 2 M NaCl, but it was absent in polysomal RNP complex. The binding of the purified protein, which has an isoelectric point of 7.3, to glucose-containing glycoconjugates depends on the presence of Ca2+ and Mg2+. Using closed nuclear envelope vesicles as a system to study nuclear transport of RNA, it was shown that both entrapped polysomal mRNA and nuclear RNA precursors are readily …
Muscle protein synthesis, mTORC1/MAPK/Hippo signaling, and capillary density are altered by blocking of myostatin and activins
2012
Loss of muscle mass and function occurs in various diseases. Myostatin blocking can attenuate muscle loss, but downstream signaling is not well known. Therefore, to elucidate associated signaling pathways, we used the soluble activin receptor IIb (sActRIIB-Fc) to block myostatin and activins in mice. Within 2 wk, the treatment rapidly increased muscle size as expected but decreased capillary density per area. sActRIIB-Fc increased muscle protein synthesis 1–2 days after the treatment correlating with enhanced mTORC1 signaling (phosphorylated rpS6 and S6K1, r = 0.8). Concurrently, increased REDD1 and eIF2Bε protein contents and phosphorylation of 4E-BP1 and AMPK was observed. In contrast, pr…