Biomaterial Database

Modification of crossbridge states by ethylene glycol in insect flight muscle. 1984

M L Clarke, and C D Rodger, and R T Tregear

Substitution of ethylene glycol for part of the solvent water changes the mechanical properties, structure and nucleotide binding of glycerol-extracted flight muscle fibres from the waterbug Lethocerus. On addition of ethylene glycol the rigor tension falls, rapidly and reversibly. With increasing glycol concentration the effect saturates at a non-zero tension. The isotonic stiffness is unchanged on adding ethylene glycol. Adding MgAMPPNP (adenylylimidodiphosphate) to a muscle fibre in 50% ethylene glycol causes a further rapid tension fall; above 100 microM AMPPNP the tension reaches zero. The isotonic stiffness of restretched muscle is then close to that of a relaxed fibre. Removal of MgAMPPNP from the bathing medium has no immediate mechanical effect. After several hours the isotonic stiffness rises to some extent; on removal of the glycol both tension and stiffness rise to rigor values within one minute. 3H-Labelled AMPPNP binds to muscle fibres in 50% ethylene glycol in a similar amount to the number of myosin heads present. The binding is tighter than that in aqueous solution and the nucleotide is only released very slowly. Upon removal of the ethylene glycol nucleotide is rapidly released. X-ray diffraction of muscle in 50% ethylene glycol reveals a highly ordered structure, in which both the 14 nm and the 38 nm layer lines are sharply sampled and are of intermediate values between rigor and relaxation. The two inner equatorial peaks are also of intermediate values. On adding MgAMPPNP the pattern resembles that of relaxed muscle. Upon removal of the nucleotide the pattern does not revert towards rigor but on removal of glycol it does. These results are interpreted in terms of changes within the myosin heads and their array within the filament lattice.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D005026	Ethylene Glycols	An ethylene compound with two hydroxy groups (-OH) located on adjacent carbons. They are viscous and colorless liquids. Some are used as anesthetics or hypnotics. However, the class is best known for their use as a coolant or antifreeze.	Dihydroxyethanes,Ethanediols,Glycols, Ethylene
D005426	Flight, Animal	The use of wings or wing-like appendages to remain aloft and move through the air.	Animal Flight,Animal Flights,Flights, Animal
D006430	Hemiptera	A large order of insects characterized by having the mouth parts adapted to piercing or sucking. It is comprised of four suborders: HETEROPTERA, Auchenorrhyncha, Sternorrhyncha, and Coleorrhyncha.	Aleurodoidea,Cicadas,Cicadelloidea,Cicadoidea,Coccoidea,Fulgoroidea,Leafhoppers,Psyllids,Psylloidea,Scale Insects,Treehoppers,Whiteflies,Homoptera,Aleurodoideas,Cicada,Cicadelloideas,Cicadoideas,Coccoideas,Fulgoroideas,Hemipteras,Homopteras,Insect, Scale,Insects, Scale,Leafhopper,Psyllid,Psylloideas,Scale Insect,Treehopper,Whitefly
D000227	Adenine Nucleotides		Adenine Nucleotide,Adenosine Phosphate,Adenosine Phosphates,Nucleotide, Adenine,Nucleotides, Adenine,Phosphate, Adenosine,Phosphates, Adenosine
D000255	Adenosine Triphosphate	An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.	ATP,Adenosine Triphosphate, Calcium Salt,Adenosine Triphosphate, Chromium Salt,Adenosine Triphosphate, Magnesium Salt,Adenosine Triphosphate, Manganese Salt,Adenylpyrophosphate,CaATP,CrATP,Manganese Adenosine Triphosphate,MgATP,MnATP,ATP-MgCl2,Adenosine Triphosphate, Chromium Ammonium Salt,Adenosine Triphosphate, Magnesium Chloride,Atriphos,Chromium Adenosine Triphosphate,Cr(H2O)4 ATP,Magnesium Adenosine Triphosphate,Striadyne,ATP MgCl2
D000266	Adenylyl Imidodiphosphate	5'-Adenylic acid, monoanhydride with imidodiphosphoric acid. An analog of ATP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It is a potent competitive inhibitor of soluble and membrane-bound mitochondrial ATPase and also inhibits ATP-dependent reactions of oxidative phosphorylation.	Adenyl Imidodiphosphate,gamma-Imino-ATP,AMP-PNP,AMPPNP,ATP(beta,gamma-NH),Adenosine 5'-(beta,gamma-Imino)triphosphate,Adenylimidodiphosphate,Adenylylimidodiphosphate,Mg AMP-PNP,Mg-5'-Adenylylimidodiphosphate,beta,gamma-imido-ATP,gamma-Imido-ATP,AMP-PNP, Mg,Imidodiphosphate, Adenyl,Imidodiphosphate, Adenylyl,Mg 5' Adenylylimidodiphosphate,Mg AMP PNP,beta,gamma imido ATP,gamma Imido ATP,gamma Imino ATP
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014961	X-Ray Diffraction	The scattering of x-rays by matter, especially crystals, with accompanying variation in intensity due to interference effects. Analysis of the crystal structure of materials is performed by passing x-rays through them and registering the diffraction image of the rays (CRYSTALLOGRAPHY, X-RAY). (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Xray Diffraction,Diffraction, X-Ray,Diffraction, Xray,Diffractions, X-Ray,Diffractions, Xray,X Ray Diffraction,X-Ray Diffractions,Xray Diffractions