Disease relevance of Npe-caged ATP

• 1. The effects of MgADP on cross-bridge kinetics were investigated using laser flash photolysis of caged ATP (P3-1(2-nitrophenyl) ethyladenosine 5'-triphosphate), in guinea-pig portal vein smooth muscle permeabilized with Staphylococcus aureus alpha-toxin [1].

High impact information on Npe-caged ATP

• Time-resolved electron microscopic analysis of the behavior of myosin heads on actin filaments after photolysis of caged ATP [2].
• 5. Force development from rigor, initiated by photolysis of caged ATP in the presence of Ca2(+)-calmodulin, is rate-limited by myosin light chain phosphorylation; it is significantly accelerated if the myosin light chains are already phosphorylated prior to photolysis.(ABSTRACT TRUNCATED AT 400 WORDS)[3]
• Kinetics of force generation by single kinesin molecules activated by laser photolysis of caged ATP [4].
• Following photolysis of caged ATP, cells without calponin that contained a nonphosphorylatable RLC shortened at 30% of the velocity and produced 65% of the isometric force of cells reconstituted with the thiophosphorylated RLC [5].
• Tension relaxation induced by pulse photolysis of caged ATP in partially crosslinked fibers from rabbit psoas muscle [6].

Biological context of Npe-caged ATP

• Myosin heads have a broad orientational distribution during isometric muscle contraction: time-resolved EPR studies using caged ATP [7].
• Unphotolyzed caged ATP is found to bind to the catalytic site of Na,K-ATPase, in competition with ATP that is produced in the flash, and the possibility has not been excluded that dissociation of unphotolyzed caged ATP and binding of ATP are involved in the Na efflux time course [8].
• These results indicate that ATP and caged ATP compete for the substrate binding site, as suggested by the ATP dependence of lambda3 and favor correlation of lambda2 with phosphoenzyme formation [9].
• 5. Caged ATP affects some site(s) involved in excitation-contraction coupling and the consequences are similar to muscle fatigue [10].
• Fibres were activated by flash photolysis of the P(3)-1-(2 nitrophenyl) ethyl ester of ATP (NPE-caged ATP), and time-resolved phosphate (P(i)) release was detected with the fluorescent protein MDCC-PBP, N-(2[1-maleimidyl]ethyl)-7-diethylamino-coumarin-3-carboxamide phosphate binding protein [11].

Anatomical context of Npe-caged ATP

• Kinetics of prephosphorylation reactions and myosin light chain phosphorylation in smooth muscle. Flash photolysis studies with caged calcium and caged ATP [12].
• Rapid photochemical liberation of 100 microM-1 mM ATP from caged ATP within a fiber caused relaxation in the absence of Ca2+ and initiated an active contraction in the presence of approximately 30 microM Ca2+ [13].
• Resealed human red cell ghosts containing caged ATP (Kaplan et al., 1978) and [3H]ADP were irradiated at 340 nm [14].
• Mechanical study of rat soleus muscle using caged ATP and X-ray diffraction: high ADP affinity of slow cross-bridges [15].
• To this end chemical relaxation studies employing light-directed generation of ATP from caged ATP have provided detailed kinetic information in muscle fibers [16].

Associations of Npe-caged ATP with other chemical compounds

• In order to test whether these motions are indications of the cross-bridge power stroke, we monitored tension and linear dichroism of the probes in single glycerol-extracted fibres of rabbit psoas muscle during mechanical transients initiated by laser pulse photolysis of caged ATP and caged ADP [17].
• The effect was not seen with photolysis of either adenosine-5'-triphosphate P3-1-(2-nitrophenyl)ethyl ester (caged ATP) or caged IP3 in cells preloaded with either heparin or (1,2-bis-(o-amino-phenoxy)ethane-N-N-N'-N' tetraacetic acid tetrapotassium salt (BAPTA) [18].
• 2. The photolysis mechanism of caged sulfate is analogous to that of P(3)-[1-(2-nitrophenyl)ethyl] ATP (caged ATP), and the photolysis efficiency is similar [19].
• Using flash photolysis of caged ATP in skinned muscle fibers from rat psoas, we examined the inhibitory effects of 2,3-butanedione monoxime (BDM) on the contraction kinetics and the rate of ATP hydrolysis of the cross-bridges at approximately 10 degrees C. The hydrolysis rate was estimated from the stiffness records [20].
• Caged ATP potentiates guanylate cyclase activity stimulated by atrial natriuretic factor in rat lung membranes [21].

Gene context of Npe-caged ATP

• ATP depletion or inhibition of protein kinase C activated the TRP channels, while photo-release of caged ATP or application of phorbol ester antagonized channels openings in the dark [22].
• To examine how the bundled actin filaments behave in myosin II-driven motility, complexes of F-actin and Dd plastin were bound to immobilized heavy meromyosin, and motility was started by photoactivating caged ATP [23].
• 7. The MDCC-PBP assay and NPE-caged ATP were used to measure the ATPase rate in single permeabilized muscle fibres of the semitendinosus muscle of the frog [24].
• The orientation of the light-chain region of myosin heads in muscle fibers was followed by polarized fluorescence from an extrinsic probe during tension transients elicited by photolysis of caged ATP [25].
• We have used saturation transfer electron paramagnetic resonance (ST-EPR) and laser-induced photolysis of caged ATP to monitor changes in the microsecond rotational dynamics of spin-labeled F-actin in the presence of myosin subfragment-1 (S1) [26].

Analytical, diagnostic and therapeutic context of Npe-caged ATP

• The estimated concentration of ATP released from caged ATP by high-pressure liquid chromatography (HPLC) was 1.3 mM [1].
• Molecular changes in the sarcoplasmic reticulum calcium ATPase during catalytic activity. A Fourier transform infrared (FTIR) study using photolysis of caged ATP to trigger the reaction cycle [27].

References