Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A single molecule of F1-ATPase has been shown to be the smallest rotary motor ever found, with a central rotor of radius approximately 1 nm turning in a stator barrel of radius approximately 5 nm. Continuous rotation of the central gamma subunit was revealed under an optical microscope by attaching to gamma a huge marker, an actin filament. In a separate study, rotation of a sliding actin filament around its axis has been revealed by attaching a small probe, a single fluorescent dye molecule, to the actin filament and detecting the orientation of the fluorophore, and thus of the actin filament, through polarization imaging. The axial rotation was slow compared to the linear sliding, indicating that myosin does not 'walk' along the helical array of actin protomers but 'runs,' skipping many protomers. The two motors above, one rotary and the other linear, represent two extreme cases of the mode of motor operation: in the F1-ATPase the two partners, the rotor and stator, never detach from each other whereas myosin touches actin only occasionally. In considering the mechanisms of these and other molecular motors, distinction between bending and binding is important. The use of huge and small probes as described above should be useful in studies of protein machines in general, as a means of detecting conformational changes in a single protein molecule during function.
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PMID:Linear and rotary molecular motors. 988 9

Observation of true rotation has been relatively rare in living systems, but there may be many molecular machines that rotate. Molecular rotations accompanying function can be imaged in real time under an optical microscope by attaching to the protein machine either a small tag such as a single fluorophore or a tag that is huge compared with the size of the protein. As an example of the former approach, axial rotation of an actin filament sliding over myosin has been measured quantitatively by attaching a fluorophore rigidly to the filament and imaging the orientation of the fluorophore continuously by polarization microscopy. As a huge tag in the latter approach, an actin filament turned out to be quite useful. Using this tag, the enzyme F1-ATPase has been shown to be a rotary stepper motor made of a single molecule. Further, the efficiency of this ATP-fueled motor has been shown to reach almost 100%. The two examples above demonstrate that one can now image conformational changes, which necessarily involve reorientation, in a single protein molecule during function. Single-molecule physiology is no longer a dream.
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PMID:Real time imaging of rotating molecular machines. 1061 28

Motor proteins, myosin, and kinesin have gamma-phosphate sensors in the switch II loop that play key roles in conformational changes that support motility. Here we report that a rotary motor, F1-ATPase, also changes its conformations upon phosphate release. The tryptophan mutation was introduced into Arg-333 in the beta subunit of F1-ATPase from thermophilic Bacillus PS3 as a probe of conformational changes. This residue interacts with the switch II loop (residues 308-315) of the beta subunit in a nucleotide-bound conformation. The addition of ATP to the mutant F1 subcomplex alpha3beta(R333W)3gamma caused transient increase and subsequent decay of the Trp fluorescence. The increase was caused by conformational changes on ATP binding. The rate of decay agreed well with that of phosphate release monitored by phosphate-binding protein assays. This is the first evidence that the beta subunit changes its conformation upon phosphate release, which may share a common mechanism of exerting motility with other motor proteins.
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PMID:F1-ATPase changes its conformations upon phosphate release. 1188 Mar 67

Oxidative stress is implicated in a broad variety of chronic and acute diseases, including such age-related diseases as diabetes. To understand at the protein level cellular damage caused by the stress, we developed a proteomic method, in which protein carbonyls were derivatized with biotin hydrazide followed by two-dimensional gel electrophoresis. The method, being capable of analyzing high-molecular-mass proteins as large as myosin heavy chains (molecular mass approximately 200 kDa), was applied to detecting protein carbonyls in muscles of a diabetes model Otsuka Long-Evans Tokushima Fatty (OLETF) rat and a control Long-Evans Tokushima Otsuka (LETO) rat. A number of proteins, including mitochondrial ATP synthase beta-chain, desmin, actin, and myosin, were found carbonylated. Our method would provide a means toward clarifying a comprehensive view of oxidative modifications of proteins during a long progression of age-related diseases and understanding the mechanism of the onset, progression, and complication of the diseases.
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PMID:Proteomic method detects oxidatively induced protein carbonyls in muscles of a diabetes model Otsuka Long-Evans Tokushima Fatty (OLETF) rat. 1249 75

The synthesis of ATP from ADP and inorganic phosphate by F1F0-ATP synthase, the universal enzyme in biological energy conversion, using the energy of a transmembrane gradient of ions, and the use of ATP by the myosin-actin system to cause muscular contraction are among the most fundamental processes in biology. Both the ATP synthase and the myosin-actin may be looked upon as molecular machines. A detailed analysis of the molecular mechanisms of energy transduction by these molecular machines has been carried out in order to understand the means by which living cells produce and consume energy. These mechanisms have been compared with each other and their biological implications have been discussed. The thermodynamics of energy coupling in the oxidative phosphorylation process has been developed and the consistency of the mechanisms with the thermodynamics has been explored. Novel engineering applications that can result have been discussed in detail and several directions for future work have been pointed out.
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PMID:Molecular mechanisms of energy transduction in cells: engineering applications and biological implications. 1293 95

In this work, we report on a study of the structure-function relationships for three families of motor proteins, including kinesins, myosins, and F1-ATPases, by using a version of the simple elastic-network model of large-scale protein motions originally proposed by Tirion [Tirion, M. (1996) Phys. Rev. Lett. 77, 1905-1908]. We find a surprising dichotomy between kinesins and the other motor proteins (myosins and F1-ATPase). For the latter, there exist one or two dominant lowest-frequency modes (one for myosin, two for F1-ATPase) obtained from normal-mode analysis of the elastic-network model, which overlap remarkably well with the measured conformational changes derived from pairs of solved crystal structures in different states. Furthermore, we find that the computed global conformational changes induced by the measured deformation of the nucleotide-binding pocket also overlap well with the measured conformational changes, which is consistent with the "nucleotide-binding-induced power-stroke" scenario. In contrast, for kinesins, this simplicity breaks down. Multiple modes are needed to generate the measured conformational changes, and the computed displacements induced by deforming the nucleotide-binding pocket also overlap poorly with the measured conformational changes, and are insufficient to explain the large-scale motion of the relay helix and the linker region. This finding may suggest the presence of two different mechanisms for myosins and kinesins, despite their strong evolutionary ties and structural similarities.
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PMID:A comparative study of motor-protein motions by using a simple elastic-network model. 1458 32

Oral tongue carcinoma is an aggressive tumor that particularly affects chronic smokers, drinkers and betel squid chewers. Patients often present symptoms at a late stage, and there is a high recurrence rate after treatment. In this article, we report the first proteomic analysis of oral tongue carcinoma to globally search for tumor related proteins. Apart from helping us to understand the molecular pathogenesis of the carcinoma, these proteins may also have potential clinical applications as biomarkers, enabling the tumor to be identified at an early stage in high risk individuals, treatment response to be predicted, and residual or recurrent carcinoma to be detected sooner after treatment. The protein expression profiles of ten oral tongue squamous cell carcinomas and their matched normal mucosal resection margins were examined by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization-time of flight mass spectroscopy. A number of tumor-associated proteins including heat shock protein (HSP)60, HSP27, alpha B-crystalline, ATP synthase beta, calgranulin B, myosin, tropomyosin and galectin 1 were consistently found to be significantly altered in their expression levels in tongue carcinoma tissues, compared with their paired normal mucosae. The expression profile portrays a global protein alteration that appears specific to oral tongue cancer. The potential of utilizing these tumor related proteins for screening cancer and monitoring recurrence warrants further investigation.
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PMID:Identification of tumor-associated proteins in oral tongue squamous cell carcinoma by proteomics. 1473 Jun 89

The molecular motor, myosin, undergoes conformational changes in order to convert chemical energy into force production. Based on kinetic and structural considerations, we assert that three crystal forms of the myosin V motor delineate the conformational changes that myosin motors undergo upon detachment from actin. First, a motor domain structure demonstrates that nucleotide-free myosin V adopts a specific state (rigor-like) that is not influenced by crystal packing. A second structure reveals an actomyosin state that favors rapid release of ADP, and differs from the rigor-like state by a P-loop rearrangement. Comparison of these structures with a third structure, a 2.0 angstroms resolution structure of the motor bound to an ATP analog, illuminates the structural features that provide communication between the actin interface and nucleotide-binding site. Paramount among these is a region we name the transducer, which is composed of the seven-stranded beta-sheet and associated loops and linkers. Reminiscent of the beta-sheet distortion of the F1-ATPase, sequential distortion of this transducer region likely controls sequential release of products from the nucleotide pocket during force generation.
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PMID:Three myosin V structures delineate essential features of chemo-mechanical transduction. 1551 Feb 14

Kinesin, myosin and F1-ATPase are multi-domain molecular motors with multiple catalytic subunits. The motor mechanochemics are achieved via the conversion of ATP hydrolysis energy into forces and motions. We find that the catalysis of these molecular motors do not follow the simple Michaelis-Menten mechanism. The motor activities, such as the hydrolysis or processive rates, of kinesin, myosin and F1-ATPase have a complex ATP-dependent cooperativity. To understand this complexity in kinetics and mechanochemics, we develop a conformation correlation theory of cooperativity for the ATP-fueled motor proteins. The quantitative analysis and simulations indicate that cooperativity is induced by the conformational coupling of binding states of different subunits and prevails in the motor activities.
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PMID:Cooperativity in the motor activities of the ATP-fueled molecular motors. 1614 May 97

We used microarray technology to study differentially expressed genes in white spot syndrome virus (WSSV)-infected shrimp. A total of 3136 cDNA targets, including 1578 unique genes from a cephalothorax cDNA library and 1536 cDNA clones from reverse and forward suppression subtractive hybridization (SSH) libraries of Fenneropenaeus chinensis, plus 14 negative and 8 blank control clones, were spotted onto a 18 x 18 mm area of NH(2)-modified glass slides. Gene expression patterns in the cephalothorax of shrimp at 6 h after WSSV injection and moribund shrimp naturally infected by WSSV were analyzed. A total of 105 elements on the arrays showed a similar regulation pattern in artificially infected shrimp and naturally infected moribund shrimp; parts of the results were confirmed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The up-regulated expression of immune-related genes, including heat shock proteins (HSP70 and HSP90), trehalose-phosphate synthase (TPS), ubiquitin C, and so forth, were observed when shrimp were challenged with WSSV. Genes including myosin LC2, ATP synthase A chain, and arginine kinase were found to be down-regulated after WSSV infection. The expression of housekeeping genes such as actin, elongation factor, and tubulin is not stable, and so these genes are not suitable as internal standards for semiquantitative RT-PCR when shrimp are challenged by WSSV. As a substitute, we found that triosephosphate isomerase (TPI) was an ideal candidate of interstandards in this situation.
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PMID:Discovery of the genes in response to white spot syndrome virus (WSSV) infection in Fenneropenaeus chinensis through cDNA microarray. 1679 54


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