W . Ross Ellington

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Phosphagens are phosphorylated guanidino compounds that are linked to energy state and ATP hydrolysis by corresponding phosphagen kinase reactions: phosphagen + MgADP + H(+) <--> guanidine acceptor + MgATP. Eight different phosphagens (and corresponding phosphagen kinases) are found in the animal kingdom distributed along distinct phylogenetic lines. By(More)
Arginine kinase belongs to the family of enzymes, including creatine kinase, that catalyze the buffering of ATP in cells with fluctuating energy requirements and that has been a paradigm for classical enzymological studies. The 1.86-A resolution structure of its transition-state analog complex, reported here, reveals its active site and offers direct(More)
In vertebrate tissues, the only phosphagen is phosphocreatine (PC), and the corresponding phosphotransferase is creatine phosphokinase (CPK). Among invertebrates, a variety of phosphotransferase reactions are found in addition to CPK, including arginine phosphokinase (APK), glycocyamine phosphokinase (GPK), taurocyamine phosphokinase (TPK) and lombricine(More)
Arginine kinase (AK), catalyzing the reversible transfer of phosphate from MgATP to arginine yielding phosphoarginine and MgADP, is widely distributed throughout the invertebrates and is also present in certain protozoa. Typically, these proteins are found as monomers targeted to the cytoplasm, but true dimeric and contiguous dimeric AKs as well as(More)
The creatine kinase (CK)/phosphocreatine (PCr) energy buffering system is widespread in animal groups. Recent genomic sequencing and experimental results support the view that the capacity for creatine biosynthesis and membrane transport may have evolved quite early, perhaps coincident with CK. Conventional wisdom would suggest that CK evolved from an(More)
Taurocyamine kinase (TK) is a member of the highly conserved family of phosphagen kinases that includes creatine kinase (CK) and arginine kinase. TK is found only in certain marine annelids. In this study we used PCR to amplify two cDNAs coding for TKs from the polychaete Arenicola brasiliensis, cloned these cDNAs into the pMAL plasmid and expressed the TKs(More)
Arginine kinase (AK) is a member of the guanidino kinase family that plays an important role in buffering ATP concentration in cells with high and fluctuating energy demands. The AK specifically catalyzes the reversible phosphoryl transfer between ATP and arginine. We have determined the crystal structure of AK from the horseshoe crab (Limulus polyphemus)(More)
External fertilization is considered to be the primitive condition in metazoans. The spermatozoa of such organisms typically display a common primitive-type morphology that is present in a range of phyla. These spermatozoa are extremely polarized cells in that the site of ATP synthesis (mitochondria in midpiece) is located at large diffusion distances from(More)
Catalytic properties and potential functional coupling with the adenine nucleotide translocase (ANT) were studied in arginine kinase (AK) from the mitochondria of the heart of the horseshoe crab,Limulus polyphemus. Kinetic constants determined for cytoplasmic AK, AK in mitochondria, and mitochondrial AK tightly bound to membrane fragments were virtually(More)
Lombricine kinase (LK) from the body wall muscle of the earthworm Eisenia foetida was purified to homogeneity. The enzyme was shown to be a dimer consisting of 40 kDa subunits. The cDNA-derived amino acid sequence of 370 residues of Eisenia LK was determined. The validity of the sequence was supported by chemical sequencing of internal tryptic peptides.(More)