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Showing 1 to 20 of 126 for “"ATP hydrolysis"”.
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Understanding the ATP hydrolysis mechanism in myosin using computer simulation techniques
… that convert energy from nucleoside triphosphate hydrolysis into mechanical work. A prominent example is myosin which drives muscle contraction and a large number of additional cellular transport phenomena in all living organisms. While hydrolyzing ATP, myosin translocates along an actin filament. …
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The CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) Channel: Anion Permeation, and Regulation by Adenylyl Cyclase and ATP Hydrolysis
… gating, and with channels locked open using the ATP analog AMP-PNP. The sequence of relative permeabilities was unaffected by channel gating, and was: NO<sub>3</sub><sup>-</sup> (1.74 ± 0.04) > Br<sup>-</sup> (1.51 ± 0.06) > I<sup>-</sup> (1.30 ± 0.07) > Cl<sup>-</sup> (1.0) > F<sup>-</sup> (0.25 …
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Molecular Mechanism of MDA5 RNA Sensing in Innate Immunity and Disease Pathogenesis
… and LGP2. I showed the cooperative nature of ATP hydrolysis in MDA5-dsRNA filaments. I discovered that adjacent MDA5 subunits in a filament hydrolyse ATP cooperatively, leading to coupled filament disassembly which allows MDA5 to displace tightly bound proteins from dsRNA. Unlike MDA5, LGP2 …
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Creation and analysis of chimeras of spinach and tobacco Rubisco activase
… the activity of Rubisco in vivo and hydrolyzes ATP. Regulation is achieved by promoting carbamylation of Rubisco (required for catalytic activation) as well as freeing Rubisco of various other sugar phosphates which either interfere with carbamylation or diminish the activity of carbamylated …
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Cooperativity and communication in archaeal Cdc48·20S, an ancient proteolytic machine
ATP dependent proteolysis is a process essential for life and is carried out by AAA+ proteases. AAA+ unfoldases use the energy of ATP hydrolysis to power the unfolding and translocation of protein substrates into compartmentalized peptidases for regulated proteolysis. Cdc48 is a highly conserved …
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Structure of the GP16 ATPase from the φ29 dsDNA packaging motor
… motor. This motor is powered by an oligomeric ATPase, gp16, or gene product 16, that converts energy obtained from ATP hydrolysis into translocation of dsDNA. In this study, we solved the gp16 ATPase structure via X-ray crystallography. The resultant monomeric structure indicated that gp16 …
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Single molecule fluorescence studies of replicative helicases
… the chemical energy of nucleotide triphosphate hydrolysis into mechanical energy for translocation on single stranded (ss) DNA and unwinding of double stranded (ds) DNA. All of the 12 known replicative helicases are hexameric helicases that are ring-shaped in structure and are homohexamers with …
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Comparative Studies of Processivity Clamp Loader ATP Site Function
… clamps to ensure polymerase processivity. An ATP-dependent clamp loader topologically links the clamp around DNA in a multi-step mechanism. Clamp loaders are ring-shaped pentamers of AAA+ subunits. The pentamer complex contains 3-4 ATP sites, each located at the interface of two subunits. In …
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Mechanistic investigation of coordinated conformational changes in multisubunit ion channels and enzymes
… conformational changes in two systems: the ATP-sensitive potassium (KATP) channel and the ATP-dependent bacterial protease, ClpAP. KATP channels consist of two protein subunits: a pore-forming subunit, Kir6.2 and a regulatory subunit, SUR1. Kir6.2 is an inwardly rectifying potassium channel, …
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AN INSIGHT INTO DIFFERENT MODES OF REMODELER REGULATION: FOCUS ON SACCHAROMYCES CEREVISIAE SWI/SNF
ATP dependent chromatin remodelers use the energy from ATP hydrolysis to move, disassemble or alter the composition of nucleosomes. Though all remodelers share a conserved ATP hydrolysis and DNA translocase domain, their biochemical actions and in-vivo characteristics differ because of their …
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Interactions of ATP, ADP and magnesium ion with rubisco activase and their effects on rubisco activation
… activation of rubisco in the presence of ATP and Mg$\sp{2+}$. The fluorescent dye 1-anilinonaphthalene-8-sulfonate was used to study the binding of rubisco activase with ligands. The results indicated that rubisco activase bound ADP (k$\sb{\rm d}$ = 0.76 $\mu$M) more tightly than ATP …
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Nucleotide binding and conformational switching in the hexameric ring of a AAA+ machine
ATP-powered proteases enforce protein quality-control and regulation in all domains of life. ClpX, a AAA+ ring homohexamer, uses the energy of ATP binding and hydrolysis to power conformational changes that unfold and translocate target proteins into the ClpP peptidase for degradation. X-ray …
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THE INTERPLAY OF HISTONE CHAPERONE NAP1 WITH SWI/SNF FAMILY OF CHROMATIN REMODELLERS IN S.cerevisiae
… is one of the mechanisms by which the ATP dependent chromatin remodelers remodel the nucleosomes. However nucleosome remodeling is also regulated by other factors like covalent modifications marks (methylation, acetylation etc. of both histones and chromatin remodelers). and histone …
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Role of communication between subunits and enzymes in ClpXP-mediated substrate unfolding and degradation
… highly conserved AAA+ Clp/Hsp100 proteins are ATPases which function as disassembly chaperones as well as essential components of energy-dependent proteases. For example, the ClpX ATPase disassembles macromolecular complexes and combines with the ClpP peptidase to form ClpXP, a molecular …
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On the depolymerization of actin filaments
… (disassembly) of actin filaments. Actin binds ATP and within the filament, actin-bound ATP is hydrolyzed into ADP on a time scale of a few minutes. As ADP-actin dissociates faster from the filament ends than ATP-actin, the filament becomes less stable as it grows older. Recent single filament …
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Substrate denaturation and translocation by a proteolytic machine
… processes by harnessing energy from cycles of ATP hydrolysis. ClpX is a relatively simple AAA+ ATPase that powers regulated protein degradation by binding native protein substrates, denaturing them, and translocating the unfolded molecule into the sequestered proteolytic compartment of its …
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Mechanism of Light Regulation of Rubisco by Rubisco Activase via Thioredoxin -F in Arabidopsis Thaliana
… Rubisco activity. At physiological ratios of ADP/ATP, the 46-kDa isoform has minimal ATP hydrolysis and Rubisco activation activity in comparison with 43-kDa isoform. Analysis of a series of carboxyl-terminal deletion and Ala substitution mutants of the 46-kDa isoform revealed that the presence of …
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Control of HslUV protease function by nucleotide binding and hydrolysis
… using the power of nucleotide binding and hydrolysis to drive conformational changes in themselves and their target substrates. Like other AAA+ proteases, HslUV recognizes, unfolds, translocates, and degrades substrate proteins in an ATP-dependent manner. Understanding how nucleotides …
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STRUCTURAL AND FUNCTIONAL DELINEATION OF SUBUNITS AND DOMAINS IN THE SACCHAROMYCES CEREVISIAE SWI/SNF COMPLEX
Chromatin remodelers are ATP-dependent multisubunit assemblies that regulate transcription and other processes by altering DNA-histone contacts. The mechanism of action is based on the transduction of energy released by ATP hydrolysis to translocation on DNA and ultimately the movement of histones …
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Single-molecule visualization of conformational changes in the SecA ATPase
… membrane, via the SecYEG channel, by the SecA ATPase. Relatively little is understood of how SecA couples ATP hydrolysis to polypeptide translocation. X-ray crystallography and many biochemical studies support a model in which the two-helix finger (2HF) of SecA pushes the polypeptide through …
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