Biomaterial Database

An investigation of the SH1-SH2 and SH1-ATPase distances in myosin subfragment-1 by resonance energy transfer using nanosecond fluorimetry. 1985

H C Cheung, and F Gonsoulin, and F Garland

The separation between the two reactive thiols SH1 (Cys-704) and SH2 (Cys-694) and that between SH1 and the active site of myosin subfragment-1 were further investigated by Förster energy transfer techniques. The SH1-SH2 distance was determined with the probe 5-[[2-[(iodoacetyl)amino]ethyl] amino]naphthalene-1-sulfonic acid (AEDANS) attached to SH1 as the energy donor and 5-(iodoacetamido)fluorescein (IAF) attached to SH2 as energy acceptor. The results derived from measurements of donor lifetimes yielded a donor-acceptor separation in the range 26-52 A, with the distance R(2/3) based on rapid and isotropic probe motions being 40 A. These parameters were not sensitive to added MgADP, in agreement with previous results obtained by using the steady-state method. The SH1-SH2 distance was also determined with AEDANS attached to SH1 and N-(4-dimethylamino-3,5-dinitrophenyl)maleimide (DDPM) attached to SH2. The range in R for the AEDANS/DDPM pair was 12-36 A, with R(2/3) equal to 27 A. The transfer efficiency between these two probes increased by an average of 38% upon addition of MgADP. These results are in agreement with those previously reported (Dalbey, R.E., Weiel, J. and Yount, R.G. (1983) Biochemistry 22, 4696-4706), but the uncertainty in choosing an appropriate value of the orientation factor to describe the AEDANS-DDPM separation does not allow a unique interpretation of the observed increase in energy transfer because it could reflect either an increase in the average orientation factor or a decrease in the donor-acceptor separation. Nevertheless, the results are consistent with the notion that nucleotide binding induces structural perturbations that can be sensed by SH1 and SH2. The distance between SH1 and the ATPase site was determined with AEDANS linked to SH1 and the nucleotide analogue 2'(3')-O-(2,4,6-trinitrophenyl)adenosine 5'-diphosphate (TNP-ADP) noncovalently bound to the active site as energy acceptor. The bound TNP-ADP was highly immobilized, with a depolarization factor approaching unity. The separation between AEDANS at SH1 and TNP-ADP at the active site was in the range 15-44 A. The actual minimal separation between SH1 and the active site is probably less than 15 A, which suggests that direct interaction between the two sites cannot be ruled out from energy transfer results.

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.
D009218	Myosins	A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.	Myosin ATPase,ATPase, Actin-Activated,ATPase, Actomyosin,ATPase, Myosin,Actin-Activated ATPase,Actomyosin ATPase,Actomyosin Adenosinetriphosphatase,Adenosine Triphosphatase, Myosin,Adenosinetriphosphatase, Actomyosin,Adenosinetriphosphatase, Myosin,Myosin,Myosin Adenosinetriphosphatase,ATPase, Actin Activated,Actin Activated ATPase,Myosin Adenosine Triphosphatase
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D003545	Cysteine	A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.	Cysteine Hydrochloride,Half-Cystine,L-Cysteine,Zinc Cysteinate,Half Cystine,L Cysteine
D004735	Energy Transfer	The transfer of energy of a given form among different scales of motion. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed). It includes the transfer of kinetic energy and the transfer of chemical energy. The transfer of chemical energy from one molecule to another depends on proximity of molecules so it is often used as in techniques to measure distance such as the use of FORSTER RESONANCE ENERGY TRANSFER.	Transfer, Energy
D000244	Adenosine Diphosphate	Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.	ADP,Adenosine Pyrophosphate,Magnesium ADP,MgADP,Adenosine 5'-Pyrophosphate,5'-Pyrophosphate, Adenosine,ADP, Magnesium,Adenosine 5' Pyrophosphate,Diphosphate, Adenosine,Pyrophosphate, Adenosine
D000251	Adenosine Triphosphatases	A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.	ATPases,Adenosinetriphosphatase,ATPase,ATPase, DNA-Dependent,Adenosine Triphosphatase,DNA-Dependent ATPase,DNA-Dependent Adenosinetriphosphatases,ATPase, DNA Dependent,Adenosinetriphosphatases, DNA-Dependent,DNA Dependent ATPase,DNA Dependent Adenosinetriphosphatases,Triphosphatase, 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