The β-hairpin region of the cyanobacterial F1-ATPase γ-subunit plays a regulatory role in the enzyme activity

2019 ◽  
Vol 476 (12) ◽  
pp. 1771-1780 ◽  
Author(s):  
Kentaro Akiyama ◽  
Kumiko Kondo ◽  
Kosuke Inabe ◽  
Satoshi Murakami ◽  
Ken-ichi Wakabayashi ◽  
...  
Keyword(s):  
Critical Role ◽  
Enzyme Regulation ◽  
Specific Region ◽  
Hairpin Structure ◽  
F1 Atpase ◽  
Photosynthetic Organisms ◽  
Γ Subunit ◽  
Central Stalk ◽  
Function Relationship ◽  
Relationship Of

Abstract The γ-subunit of cyanobacterial and chloroplast ATP synthase, the rotary shaft of F1-ATPase, equips a specific insertion region that is only observed in photosynthetic organisms. This region plays a physiologically pivotal role in enzyme regulation, such as in ADP inhibition and redox response. Recently solved crystal structures of the γ-subunit of F1-ATPase from photosynthetic organisms revealed that the insertion region forms a β-hairpin structure, which is positioned along the central stalk. The structure–function relationship of this specific region was studied by constraining the expected conformational change in this region caused by the formation of a disulfide bond between Cys residues introduced on the central stalk and this β-hairpin structure. This fixation of the β-hairpin region in the α3β3γ complex affects both ADP inhibition and the binding of the ε-subunit to the complex, indicating the critical role that the β-hairpin region plays as a regulator of the enzyme. This role must be important for the maintenance of the intracellular ATP levels in photosynthetic organisms.

Structure of the γ–ε complex of cyanobacterial F1-ATPase reveals a suppression mechanism of the γ subunit on ATP hydrolysis in phototrophs

2018 ◽  
Vol 475 (18) ◽  
pp. 2925-2939 ◽  
Author(s):  
Satoshi Murakami ◽  
Kumiko Kondo ◽  
Shinya Katayama ◽  
Satoshi Hara ◽  
Ei-ichiro Sunamura ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Atp Hydrolysis ◽  
Critical Role ◽  
Structural Data ◽  
Hairpin Structure ◽  
Critical Function ◽  
F1 Atpase ◽  
Γ Subunit ◽  
Suppression Mechanism ◽  
Biochemical Analyses

F1-ATPase forms the membrane-associated segment of F0F1-ATP synthase — the fundamental enzyme complex in cellular bioenergetics for ATP hydrolysis and synthesis. Here, we report a crystal structure of the central F1 subcomplex, consisting of the rotary shaft γ subunit and the inhibitory ε subunit, from the photosynthetic cyanobacterium Thermosynechococcus elongatus BP-1, at 1.98 Å resolution. In contrast with their homologous bacterial and mitochondrial counterparts, the γ subunits of photosynthetic organisms harbour a unique insertion of 35–40 amino acids. Our structural data reveal that this region forms a β-hairpin structure along the central stalk. We identified numerous critical hydrogen bonds and electrostatic interactions between residues in the hairpin and the rest of the γ subunit. To elaborate the critical function of this β-hairpin in inhibiting ATP hydrolysis, the corresponding domain was deleted in the cyanobacterial F1 subcomplex. Biochemical analyses of the corresponding α3β3γ complex confirm that the clinch of the hairpin structure plays a critical role and accounts for a significant interaction in the α3β3 complex to induce ADP inhibition during ATP hydrolysis. In addition, we found that truncating the β-hairpin insertion structure resulted in a marked impairment of the interaction with the ε subunit, which binds to the opposite side of the γ subunit from the β-hairpin structure. Combined with structural analyses, our work provides experimental evidence supporting the molecular principle of how the insertion region of the γ subunit suppresses F1 rotation during ATP hydrolysis.

scholarly journals How release of phosphate from mammalian F1-ATPase generates a rotary substep

2015 ◽  
Vol 112 (19) ◽  
pp. 6009-6014 ◽  
Author(s):  
John V. Bason ◽  
Martin G. Montgomery ◽  
Andrew G. W. Leslie ◽  
John E. Walker
Keyword(s):  
Phosphate Binding ◽  
Atpase Inhibitor ◽  
Phosphate Release ◽  
F1 Atpase ◽  
Γ Subunit ◽  
Central Stalk ◽  
Catalytic Sites ◽  
Equivalent Site ◽  
Sequential Binding ◽  
A Site

The rotation of the central stalk of F1-ATPase is driven by energy derived from the sequential binding of an ATP molecule to its three catalytic sites and the release of the products of hydrolysis. In human F1-ATPase, each 360° rotation consists of three 120° steps composed of substeps of about 65°, 25°, and 30°, with intervening ATP binding, phosphate release, and catalytic dwells, respectively. The F1-ATPase inhibitor protein, IF1, halts the rotary cycle at the catalytic dwell. The human and bovine enzymes are essentially identical, and the structure of bovine F1-ATPase inhibited by IF1 represents the catalytic dwell state. Another structure, described here, of bovine F1-ATPase inhibited by an ATP analog and the phosphate analog, thiophosphate, represents the phosphate binding dwell. Thiophosphate is bound to a site in the αEβE-catalytic interface, whereas in F1-ATPase inhibited with IF1, the equivalent site is changed subtly and the enzyme is incapable of binding thiophosphate. These two structures provide a molecular mechanism of how phosphate release generates a rotary substep as follows. In the active enzyme, phosphate release from the βE-subunit is accompanied by a rearrangement of the structure of its binding site that prevents released phosphate from rebinding. The associated extrusion of a loop in the βE-subunit disrupts interactions in the αEβE-catalytic interface and opens it to its fullest extent. Other rearrangements disrupt interactions between the γ-subunit and the C-terminal domain of the αE-subunit. To restore most of these interactions, and to make compensatory new ones, the γ-subunit rotates through 25°–30°.

scholarly journals Superresolution imaging reveals structural features of EB1 in microtubule plus-end tracking

2014 ◽  
Vol 25 (25) ◽  
pp. 4166-4173 ◽  
Author(s):  
Peng Xia ◽  
Xing Liu ◽  
Bing Wu ◽  
Shuyuan Zhang ◽  
Xiaoyu Song ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Fluorescent Protein ◽  
Critical Role ◽  
Conformational Dynamics ◽  
Spatial Dynamics ◽  
Structural Features ◽  
Live Cells ◽  
Culture Cells ◽  
Function Relationship ◽  
Relationship Of

Visualization of specific molecules and their interactions in real time and space is essential to delineate how cellular dynamics and the signaling circuit are orchestrated. Spatial regulation of conformational dynamics and structural plasticity of protein interactions is required to rewire signaling circuitry in response to extracellular cues. We introduce a method for optically imaging intracellular protein interactions at nanometer spatial resolution in live cells, using photoactivatable complementary fluorescent (PACF) proteins. Subsets of complementary fluorescent protein molecules were activated, localized, and then bleached; this was followed by the assembly of superresolution images from aggregate position of sum interactive molecules. Using PACF, we obtained precise localization of dynamic microtubule plus-end hub protein EB1 dimers and their distinct distributions at the leading edges and in the cell bodies of migrating cells. We further delineated the structure–function relationship of EB1 by generating EB1-PACF dimers (EB1wt:EB1wt, EB1wt:EB1mt, and EB1mt:EB1mt) and imaging their precise localizations in culture cells. Surprisingly, our analyses revealed critical role of a previously uncharacterized EB1 linker region in tracking microtubule plus ends in live cells. Thus PACF provides a unique approach to delineating spatial dynamics of homo- or heterodimerized proteins at the nanometer scale and establishes a platform to report the precise regulation of protein interactions in space and time in live cells.

scholarly journals In-silico analysis reveals druggable single nucleotide polymorphisms in angiotensin 1 converting enzyme involved in the onset of blood pressure

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Brenda Udosen ◽  
Opeyemi Soremekun ◽  
Chinwe Ekenna ◽  
Olaposi Idowu Omotuyi ◽  
Tinashe Chikowore ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Single Nucleotide Polymorphisms ◽  
Critical Role ◽  
Point Mutations ◽  
In Silico Analysis ◽  
Nucleotide Polymorphisms ◽  
Converting Enzyme ◽  
Single Nucleotide ◽  
Function Relationship ◽  
Relationship Of

Abstract Objective The Angiotensin 1 converting enzyme (ACE1) gene plays a critical role in regulating blood pressure and thus, it has become a major therapeutic target of antihypertensives. Single nucleotide polymorphisms (SNPs) occurring within a gene most especially at the functional segment of the genes alter the structure–function relationship of that gene. Results Our study revealed that five nsSNPs of the ACE1 gene were found to be potentially deleterious and damaging and they include rs2229839, rs14507892, rs12709442, and rs4977 at point mutations P351R, R953Q, I1018T, F1051V, and T1187M. The protein stability predictive tools revealed that all the nsSNPs decreased stability of the protein and the Consurf server which estimates the evolutionary conservation profile of a protein showed that three mutants were in the highly conserved region. In conclusion, this study predicted potential druggable deleterious mutants that can be further explored to understand the pathological basis of cardiovascular disease.

scholarly journals The Mitochondrial Genome Integrity Gene, MGI1, of Kluyveromyces lactis Encodes the β-Subunit of F1-ATPase

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1445-1454 ◽  
Author(s):  
Xin Jie Chen ◽  
G Desmond Clark-Walker
Keyword(s):  
Mitochondrial Genome ◽  
Kluyveromyces Lactis ◽  
Three Dimensional ◽  
Genome Integrity ◽  
Dimensional Structure ◽  
Deletion Mutants ◽  
Β Subunit ◽  
Gain Of Function ◽  
F1 Atpase ◽  
Γ Subunit

In a previous report, we found that mutations at the mitochondrial genome integrity locus, MGI1, can convert Kluyveromyces lactis into a petite-positive yeast. In this report, we describe the isolation of the MGI1 gene and show that it encodes the β-subunit of the mitochondrial F1-ATPase. The site of mutation in four independently isolated mgi1 alleles is at Arg435, which has changed to Gly in three cases and Ile in the fourth isolate. Disruption of MGI1 does not lead to the production of mitochondrial genome deletion mutants, indicating that an assembled F1 complex is needed for the “gain-of-function” phenotype found in mgi1 point mutants. The location of Arg435 in the β-subunit, as deduced from the three-dimensional structure of the bovine F1-ATPase, together with mutational sites in the previously identified mgi2 and mgi5 alleles, suggests that interaction of the β- and α- (MGI2) subunits with the γ-subunit (MGI5) is likely to be affected by the mutations.

Structure–property–function relationship of fluorescent conjugated microporous polymers

2021 ◽  
Author(s):  
M. G. Monika Bai ◽  
H. Vignesh Babu ◽  
V. Lakshmi ◽  
M. Rajeswara Rao
Keyword(s):  
Long Range ◽  
Structure Property ◽  
Porous Organic Polymers ◽  
Aggregation Induced Emission ◽  
Microporous Polymers ◽  
Exciton Migration ◽  
Wide Range ◽  
Function Relationship ◽  
Relationship Of ◽  
Conjugated Microporous Polymers

Fluorescent porous organic polymers are a unique class of materials owing to their strong aggregation induced emission, long range exciton migration and permanent porosity, thus envisioned to possess a wide range of applications (sensing, OLEDs).

Morphology-Function Relationship of Thermoelectric Nanocomposite Films from PEDOT:PSS with Silicon Nanoparticles

2017 ◽  
Vol 3 (8) ◽  
pp. 1700181 ◽  
Author(s):  
Nitin Saxena ◽  
Mihael Čorić ◽  
Anton Greppmair ◽  
Jan Wernecke ◽  
Mika Pflüger ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Nanocomposite Films ◽  
Function Relationship ◽  
Relationship Of

Medullary lateral tegmental field: control of respiratory rate and vagal lung inflation afferent influences on sympathetic nerve discharge

2005 ◽  
Vol 288 (5) ◽  
pp. R1396-R1410 ◽  
Author(s):  
Shaun W. Phillips ◽  
Gerard L. Gebber ◽  
Susan M. Barman
Keyword(s):  
Respiratory Rate ◽  
Sympathetic Nerve ◽  
Artificial Ventilation ◽  
Critical Role ◽  
Lung Inflation ◽  
Chemical Inactivation ◽  
A Value ◽  
Relationship Of ◽  
The Relationship ◽  
Nerve Discharge

We used spectral analysis and event-triggered averaging to determine the effects of chemical inactivation of the medullary lateral tegmental field (LTF) on 1) the relationship of intratracheal pressure (ITP, an index of vagal lung inflation afferent activity) to sympathetic nerve discharge (SND) and phrenic nerve activity (PNA) and 2) central respiratory rate in paralyzed, artificially ventilated dial-urethane-anesthetized cats. ITP-SND coherence value at the frequency of artificial ventilation was significantly ( P < 0.05; n = 18) reduced from 0.73 ± 0.04 (mean ± SE) to 0.24 ± 0.04 after bilateral microinjection of muscimol into the LTF. Central respiratory rate was unexpectedly increased in 12 of these experiments (0.28 ± 0.03 vs. 0.95 ± 0.25 Hz). The ITP-PNA coherence value was variably affected by chemical inactivation of the LTF. It was unchanged when central respiratory rate was also not altered, decreased when respiratory rate was increased above the rate of artificial ventilation, and increased when respiratory rate was raised from a value below the rate of artificial ventilation to the same frequency as the ventilator. Chemical inactivation of the LTF increased central respiratory rate in four of six vagotomized cats but did not significantly affect the PNA-SND coherence value. These data demonstrate that the LTF 1) plays a critical role in mediating the effects of vagal lung inflation afferents on SND but not PNA, 2) helps maintain central respiratory rate in the physiological range, but 3) is not involved in the coupling of central respiratory and sympathetic circuits.

scholarly journals High-resolution single-cell 3D-models of chromatin ensembles during Drosophila embryogenesis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Qiu Sun ◽  
Alan Perez-Rathke ◽  
Daniel M. Czajkowsky ◽  
Zhifeng Shao ◽  
Jie Liang
Keyword(s):  
High Resolution ◽  
Single Cell ◽  
3D Models ◽  
Computational Method ◽  
Midblastula Transition ◽  
Genome Wide ◽  
Large Ensembles ◽  
Chromatin Folding ◽  
Function Relationship ◽  
Relationship Of

AbstractSingle-cell chromatin studies provide insights into how chromatin structure relates to functions of individual cells. However, balancing high-resolution and genome wide-coverage remains challenging. We describe a computational method for the reconstruction of large 3D-ensembles of single-cell (sc) chromatin conformations from population Hi-C that we apply to study embryogenesis in Drosophila. With minimal assumptions of physical properties and without adjustable parameters, our method generates large ensembles of chromatin conformations via deep-sampling. Our method identifies specific interactions, which constitute 5–6% of Hi-C frequencies, but surprisingly are sufficient to drive chromatin folding, giving rise to the observed Hi-C patterns. Modeled sc-chromatins quantify chromatin heterogeneity, revealing significant changes during embryogenesis. Furthermore, >50% of modeled sc-chromatin maintain topologically associating domains (TADs) in early embryos, when no population TADs are perceptible. Domain boundaries become fixated during development, with strong preference at binding-sites of insulator-complexes upon the midblastula transition. Overall, high-resolution 3D-ensembles of sc-chromatin conformations enable further in-depth interpretation of population Hi-C, improving understanding of the structure-function relationship of genome organization.

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