Comparison of the structure and function of ribulosebisphosphate carboxylase–oxygenase from a cold-hardy and nonhardy potato species

1981 ◽  
Vol 59 (4) ◽  
pp. 280-289 ◽  
Author(s):  
Norman P. A. Huner ◽  
Jiwan P. Palta ◽  
Paul H. Li ◽  
John V. Carter
Keyword(s):  
Large Subunit ◽  
Structure And Function ◽  
Sulfhydryl Groups ◽  
Relative Mass ◽  
Nitrobenzoic Acid ◽  
Significant Difference ◽  
Ribulosebisphosphate Carboxylase ◽  
Cold Hardy ◽  
And Function ◽  
Kinetics Of

A comparison of ribulosebisphosphate carboxylase–oxygenase from the leaves of the non-acclimated, cold-hardy species, Solanum commersonii, and the nonacclimated, nonhardy species, Solanum tuberosum showed that this enzyme from the two species differed in structure and function. The results of sulfhydryl group titration with 5,5′-dithiobis(2-nitrobenzoic acid) indicated that the kinetics of titration and the number of accessible sulfhydryl groups in the native enzymes were different. After 30 min, the enzyme from the hardy species had 1.7 times fewer sulfhydryl groups titrated than that from the nonhardy species. In the presence of 1% (w/v) sodium dodecyl sulfate, the total number of sulfhydryl groups titratable with 5,5′-dithiobis-(2-nitrobenzoic acid) was the same for both species. However, this denaturant had a differential effect on the kinetics of titration with 5,5′-dithiobis(2-nitrobenzoic acid). Both enzymes had a native molecular weight of about 550 000. The quaternary structures of the two enzymes were similar with the presence of large and small subunits of 54 000 and 14 000, respectively. However, there was more polypeptide of 108 000 – 110 000 present in preparations of the enzyme from S. tuberosum than from S. commersonii. This polypeptide is an apparent dimer of the large subunit on a relative mass basis. The large subunit of the enzyme from S. tuberosum was more sensitive to the absence of reducing agent and was more sensitive to freezing and thawing than the large subunit of the enzyme from S. commersonii. Catalytic properties of both enzymes at 5 and 25 °C indicated no significant difference in the [Formula: see text] at either temperature. However, the Vmax at 5 °C for the enzyme from S. commersonii was 35% higher than that of the enzyme from S. tuberosum. In contrast, the Vmax at 25 °C for the enzyme of the hardy species was 250% lower than that of the enzyme from the nonhardy species.

Depletion and Reconstitution of Active E. Coli Ribosomes

1975 ◽  
Vol 33 ◽  
pp. 640-641
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Protein Biosynthesis ◽  
Large Subunit ◽  
High Resolution Electron Microscopy ◽  
Small Subunit ◽  
Structure And Function ◽  
Biologically Active ◽  
Biological Macromolecules ◽  
E Coli ◽  
Resolution Electron ◽  
And Function

Correlations between structure and function of biological macromolecules have been studied intensively for many years, mostly by indirect methods. High resolution electron microscopy is a unique tool which can provide such information directly by comparing the conformation of biopolymers in their biologically active and inactive state. We have correlated the structure and function of ribosomes, ribonucleoprotein particles which are the site of protein biosynthesis. 70S E. coli ribosomes, used in this experiment, are composed of two subunits - large (50S) and small (30S). The large subunit consists of 34 proteins and two different ribonucleic acid molecules. The small subunit contains 21 proteins and one RNA molecule. All proteins (with the exception of L7 and L12) are present in one copy per ribosome.This study deals with the changes in the fine structure of E. coli ribosomes depleted of proteins L7 and L12. These proteins are unique in many aspects.

Limitation of the Rate of Ribulosebisphosphate Carboxylase Activation by Carbamylation and Ribulosebisphosphate Carboxylase Activase Activity: Development and Tests of a Mechanistic Model

1996 ◽  
Vol 23 (2) ◽  
pp. 141 ◽  
Author(s):  
IE Woodrow ◽  
ME Kelly ◽  
KA Mott
Keyword(s):  
Mechanistic Model ◽  
Large Subunit ◽  
Intercellular Co2 Concentration ◽  
Rubisco Activase ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Bisphosphate Carboxylase ◽  
Ribulosebisphosphate Carboxylase ◽  
Kinetics Of ◽  
Rubisco Activation

A mechanistically-based model of light-mediated activation of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is developed. The model describes the kinetics of Rubisco activation following a relatively rapid increase in photon flux density (PPFD) from an initially low level. Underlying the model is the assumption that there are two slow processes that could potentially limit the rate of light-mediated Rubisco activation. These processes are the addition of the activator CO2 to the large subunit of Rubisco, which is accompanied by a conformational change in the enzyme (carbamylation), and activase-mediated removal of ribulose 1,5-bisphosphate from the inactive form of the enzyme. The contribution of these slow processes to the overall activation kinetics of Rubisco was resolved by measuring Rubisco activation in whole spinach leaves using non-steady-state CO2 exchange. It was found that when the change in PPFD was relatively small and a correspondingly small proportion of the Rubisco pool was activated, the kinetics of activation were highly sensitive to the intercellular CO2 concentration (ci). The apparent rate constant for activation under these conditions was found to be similar to that for the carbamylation of purified spinach Rubisco. When the change in PPFD and the proportion of Rubisco activated was relatively large, however, the kinetics of Rubisco activation were almost completely CO2 insensitive and were consistent with those of an enzyme-catalysed reaction. It is suggested that (1) CO2-insensitive activation reflects the operation of Rubisco activase and (2) the increasing CO2 sensitivity seen as the change in PPFD decreases reflects a transition to limitation by carbamylation.

scholarly journals Development of Biological E-Module Based on Contextual Teaching and Learning (CTL) Learning on Structure and Function of Plants and Animal Networks to Improve Critical Thinking Skills of Class XI MIPA SMA Students

2022 ◽  
Vol 04 (12) ◽  
Author(s):  
Yunila Fajrida ◽  
Keyword(s):  
Critical Thinking ◽  
Teaching And Learning ◽  
Thinking Skills ◽  
Structure And Function ◽  
Critical Thinking Skills ◽  
Material Structure ◽  
Animal Tissues ◽  
Significant Difference ◽  
Contextual Teaching ◽  
And Function

In the field of education, the presence of technology has helped teachers a lot in carrying out learning. Future education cannot only focus on cognitive aspects. To face various problems and challenges of the times in the future, students are expected to have much better attitudes, skills, and knowledge competencies, to be more creative, innovative, and productive. The purpose of this research is to analyze the feasibility and effectiveness of the development e-module Biology based on Contextual Teaching and Learning (CTL) on the material structure and function of plant and animal tissues to improve the critical thinking skills of students in class XI MIPA SMA that are valid, practical, and effective. The results showed that the e-module Biology based on Contextual Teaching and Learning (CTL) on the structure and function of plant and animal tissues to improve critical thinking skills of students in class XI MIPA SMA has a very valid category with a validator value of 89.33%, very practical 93.33% by Biology teachers and students with a score of 87.52% and the results of the effectiveness test of the CTL - based e-module showed that it was very effective, there was a significant difference between classes that used CTL - based e-modules and classes that did not use CTL - based e-modules . So, it can be concluded that the CTL-based Biology e-module that has been developed is very valid, very practical, and very effective.

Penetration ability of echidna spines and porcupine quills

2015 ◽  
Vol 37 (1) ◽  
pp. 23
Author(s):  
B. A. Gooden ◽  
M. L. Augee
Keyword(s):  
Muscle Tissue ◽  
Structure And Function ◽  
Opening Angle ◽  
Depth Of Penetration ◽  
Mammalian Muscle ◽  
Significant Difference ◽  
Penetration Ability ◽  
Different Response ◽  
And Function ◽  
Tachyglossus Aculeatus

The structure and function of 10 echidna (Tachyglossus aculeatus) spines and 10 cape porcupine (Hystrix africaeaustralis) quills were compared with regard to their ability to penetrate a mammalian muscle tissue analogue (10% gelatine). All specimens showed a significant correlation between the load applied and the depth of penetration into the gel. There was no significant difference between the penetration ability of the echidna spines and the porcupine quills despite the finding that quills had a significantly smaller angle at the tip of the spine (opening angle). The penetration ability of echidna spines was inversely related to the opening angle whereas there was no such correlation in porcupine quills. These findings are discussed in relation to the different response of these two species to possible predators.

[NiFe]-Hydrogenase maturation endopeptidase: structure and function

2005 ◽  
Vol 33 (1) ◽  
pp. 108-111 ◽  
Author(s):  
E. Theodoratou ◽  
R. Huber ◽  
A. Böck
Keyword(s):  
Reaction Mechanism ◽  
Substrate Specificity ◽  
Large Subunit ◽  
Cysteine Residue ◽  
Structure And Function ◽  
Metal Centre ◽  
Conformational Switch ◽  
Hydrogenase Maturation ◽  
And Function

Hydrogenase maturation endopeptidases catalyse the terminal step in the maturation of the large subunit of [NiFe]-hydrogenases. They remove a C-terminal extension from the precursor of the subunit, triggering a conformational switch that results in the bridging of the Fe and Ni atoms of the metal centre via the thiolate of a cysteine residue and in closure of the centre. This review summarizes what is known about the structure of the protein, its substrate specificity and its possible reaction mechanism.

scholarly journals Assessment of objective ocular cyclodeviation under monocular condition and binocular condition using fundus photography

2020 ◽  
Vol 5 (1) ◽  
pp. e000595
Author(s):  
Noriaki Murata ◽  
Haruo Toda ◽  
Haruna Amaki ◽  
Kanako Suzuki ◽  
Yumi Nagai ◽  
...  
Keyword(s):  
Field Tests ◽  
Structure And Function ◽  
The Other ◽  
Fundus Photography ◽  
Research Attention ◽  
Binocular Condition ◽  
Significant Difference ◽  
Retinal Structure ◽  
And Function ◽  
The Relationship

ObjectiveThe relationship between retinal structure and function of glaucomatous eyes has attracted a great deal of research attention. However, visual field tests are conducted under monocular condition, and ophthalmic imaging was performed in patients without occlusion. We aimed to assess the objective ocular cyclodeviation between monocular occlusion and binocular conditions using fundus photography.Methods and analysisThis study included 76 healthy participants. We obtained six photos of the right eye of each patient using fundus photography. Three of the photographs were taken under monocular conditions, and the other three, under binocular conditions. We measured the optic disc margin-fovea angle (MFA) of the line connecting one point of the disc limbus and the fovea. One-way repeated analysis of variance was used to compare the angles under both conditions. We also examined the direction of ocular rotation under the binocular condition regarding the monocular condition.ResultsThe MFAs were 12.12°±3.83° and 12.19°±3.95° under the monocular and binocular conditions, respectively. There was no significant difference in both MFAs (F=1.19, p=0.28). The mean cyclodeviation was 0.07°±0.80° (range: −2.40° to +2.75°). A total of 38 eyes showed excycloduction, while another 38 showed incycloduction.ConclusionSignificant cyclodeviation did not occur regardless of the existence of an occlusion. When examining the relationship between retinal structure and function, the difference in rotation angle under both conditions need not be taken into consideration if the other disease did not cause pathological cyclodeviation.

scholarly journals The SARS-CoV-2 spike reversibly samples an open-trimer conformation exposing novel epitopes

2021 ◽  
Author(s):  
Shawn M Costello ◽  
Sophie R Shoemaker ◽  
Helen T Hobbs ◽  
Annalee W Nguyen ◽  
Ching-Lin Hsieh ◽  
...  
Keyword(s):  
Structure And Function ◽  
Clinical Diagnostics ◽  
Hydrogen Deuterium Exchange ◽  
Exchange Mass Spectrometry ◽  
Alternative Conformation ◽  
Hydrogen Deuterium ◽  
Deuterium Exchange Mass Spectrometry ◽  
Binding Antibody ◽  
And Function ◽  
Kinetics Of

Current COVID-19 vaccines and many clinical diagnostics are based on the structure and function of the SARS-CoV-2 spike ectodomain. Using hydrogen deuterium exchange mass spectrometry, we have uncovered that, in addition to the prefusion structure determined by cryo-EM, this protein adopts an alternative conformation that interconverts slowly with the canonical prefusion structure. This new conformation-an open trimer-contains easily accessible RBDs. It exposes the conserved trimer interface buried in the prefusion conformation, thus exposing potential epitopes for pan-coronavirus antibody and ligand recognition. The population of this state and kinetics of interconversion are modulated by temperature, receptor binding, antibody binding, and sequence variants observed in the natural population. Knowledge of the structure and populations of this conformation will help improve existing diagnostics, therapeutics, and vaccines.

scholarly journals A COMPARATIVE CLINICAL STUDY TO EVALUATE THE EFFICACY OF ABHA GUGGULU AND YOGARAJA GUGGULU IN JANU SANDHIGATA VATA

2021 ◽  
Vol 9 (9) ◽  
pp. 1943-1950
Author(s):  
Archana B.H. Jadav ◽  
Susheel Shetty
Keyword(s):  
Clinical Trial ◽  
Statistical Difference ◽  
Structure And Function ◽  
The Body ◽  
Osteoarthritis Of The Knee ◽  
Basic Character ◽  
Significant Difference ◽  
Comparative Clinical Study ◽  
And Function ◽  
Single Blind

Mobility is the basic character of life that depends on the structural as well as the functional character of the body. As age advances, while proper nutrition is not available, the body loses its qualitative capacity for structure and function. Janu Sandhigata Vata has been explained classically by Acharyas and its lakshanas are Vata Poorna- dhrithi Sparsha, Sandhi Shotha, Sandhi Shoola and the presence of Vedana during Prasarana and Aakunchana. The lakshanas of Janu Sandhigata Vata is found to be congruent with Osteoarthritis of the Knee. Research statis- tics have shown that in India, 22% of the population shows Osteoarthritis and females slightly dominate in the incidence. Abha Guggulu and Yogaraja Guggulu are two formulations that contain the drugs of Vatahara, Shothahara, Vedanasthapaka property which will help in the management of Janu Sandhigata Vata. Methods: It was a single-blind randomized comparative clinical trial. The study was conducted on 40 subjects for 30 days. Observations were analyzed and findings were evaluated by using statistical methods. Results: The severity of symptoms markedly reduced in both the groups which is statistically significant and on comparing the effect be- tween Abha Guggulu and Yogaraja Guggulu, there was no statistical difference obtained. Conclusion: The result suggests that both Abha Guggulu and Yogaraja Guggulu had a significant effect on Janu Sandhigata Vata There was no significant difference in the effect of Abha Guggulu and Yogaraja Guggulu. Keywords: Janu Sandhigata Vata, Abha Guggulu, Yogaraja Guggulu

scholarly journals A complex CTCF binding code defines TAD boundary structure and function

2021 ◽  
Author(s):  
Li-Hsin Chang ◽  
Sourav Ghosh ◽  
Andrea Papale ◽  
Mélanie Miranda ◽  
Vincent Piras ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Dna Replication ◽  
Structure And Function ◽  
Boundary Structure ◽  
Ctcf Binding ◽  
Dependent Manner ◽  
In Silico Studies ◽  
Mouse Cells ◽  
And Function ◽  
Kinetics Of

Topologically Associating Domains (TADs) compartmentalize vertebrate genomes into sub-Megabase functional neighbourhoods for gene regulation, DNA replication, recombination and repair. TADs are formed by Cohesin-mediated loop extrusion, which compacts the DNA within the domain, followed by blocking of loop extrusion by the CTCF insulator protein at their boundaries. CTCF blocks loop extrusion in an orientation dependent manner, with both experimental and in-silico studies assuming that a single site of static CTCF binding is sufficient to create a stable TAD boundary. Here, we report that most TAD boundaries in mouse cells are modular entities where CTCF binding clusters within extended genomic intervals. Optimized ChIP-seq analysis reveals that this clustering of CTCF binding does not only occur among peaks but also frequently within those peaks. Using a newly developed multi-contact Nano-C assay, we confirm that individual CTCF binding sites additively contribute to TAD separation. This clustering of CTCF binding may counter against the dynamic DNA-binding kinetics of CTCF, which urges a re-evaluation of current models for the blocking of loop extrusion. Our work thus reveals an unanticipatedly complex code of CTCF binding at TAD boundaries that expands the regulatory potential for TAD structure and function and can help to explain how distant non-coding structural variation influences gene regulation, DNA replication, recombination and repair.

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