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Arginine Kinase (arginine + kinase)

Distribution by Scientific Domains
Chemistry66%

Selected Abstracts

Induced fit in guanidino kinases,comparison of substrate-free and transition state analog structures of arginine kinase

PROTEIN SCIENCE, Issue 1 2003
Mohammad S. Yousef
Abstract 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) in its open (substrate-free) form. The final model has been refined at 2.35 Ĺ with a final R of 22.3% (Rfree = 23.7%). The structure of the open form is compared to the previously determined structure of the transition state analog complex in the closed form. Classically, the protein would be considered two domain, but dynamic domain (DynDom) analysis shows that most of the differences between the two structures can be considered as the motion between four rigid groups of nonsequential residues. ATP binds near a cluster of positively charged residues of a fixed dynamic domain. The other three dynamic domains close the active site with separate hinge rotations relative to the fixed domain. Several residues of key importance for the induced motion are conserved within the phosphagen kinase family, including creatine kinase. Substantial conformational changes are induced in different parts of the enzyme as intimate interactions are formed with both substrates. Thus, although induced fit occurs in a number of phosphoryl transfer enzymes, the conformational changes in phosphagen kinases appear to be more complicated than in prior examples. [source]

Proteomic analysis of the venom from the endoparasitoid wasp Pteromalus puparum (Hymenoptera: Pteromalidae)

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Jia-Ying Zhu
Abstract Parasitoid venom is a complex mixture of active substances with diversified biological functions. Because of its range of activities, venom is an important resource with respect to potential application in agriculture and medicine. Only a limited number of peptides, proteins, and enzymes have been identified and characterized from parasitoid venom. Here we describe a proteomic analysis of the venom from the endoparasitoid wasp Pteromalus puparum (Hymenoptera: Pteromalidae). Venom resolved by two-dimensional electrophoresis yielded 56 protein spots with major proteins in the pI range 4,7 and molecular mass range of 25,66.2,kDa. The amino acid sequences of the proteins were identified by mass spectrometry. Several venom proteins such as calreticulin, venom acid phosphatase, serine protease, arginine kinase, serine protease homolog, aminotransferase-like venom protein, and heat shock protein 70, were identified in silico based on their amino acid sequences. The full-length cDNAs of calreticulin and arginine kinase were cloned. Calreticulin showed 62% identity with calreticulin in the venom of Cotesia rubecula. Arginine kinase showed a high level of sequence identity (92%) with its counterpart in the venom of Cyphononyx dorsalis. RT-PCR analysis revealed that the transcript levels of calreticulin and arginine kinase were developmentally changed, suggesting a possible correlation with the oviposition process. This study contributes to our appreciation of a parasitoid wasp venom composition. © 2010 Wiley Periodicals, Inc. [source]

Induced fit in guanidino kinases,comparison of substrate-free and transition state analog structures of arginine kinase

PROTEIN SCIENCE, Issue 1 2003
Mohammad S. Yousef
Abstract 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) in its open (substrate-free) form. The final model has been refined at 2.35 Ĺ with a final R of 22.3% (Rfree = 23.7%). The structure of the open form is compared to the previously determined structure of the transition state analog complex in the closed form. Classically, the protein would be considered two domain, but dynamic domain (DynDom) analysis shows that most of the differences between the two structures can be considered as the motion between four rigid groups of nonsequential residues. ATP binds near a cluster of positively charged residues of a fixed dynamic domain. The other three dynamic domains close the active site with separate hinge rotations relative to the fixed domain. Several residues of key importance for the induced motion are conserved within the phosphagen kinase family, including creatine kinase. Substantial conformational changes are induced in different parts of the enzyme as intimate interactions are formed with both substrates. Thus, although induced fit occurs in a number of phosphoryl transfer enzymes, the conformational changes in phosphagen kinases appear to be more complicated than in prior examples. [source]

Proteomic analysis of the venom from the endoparasitoid wasp Pteromalus puparum (Hymenoptera: Pteromalidae)

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Jia-Ying Zhu
Abstract Parasitoid venom is a complex mixture of active substances with diversified biological functions. Because of its range of activities, venom is an important resource with respect to potential application in agriculture and medicine. Only a limited number of peptides, proteins, and enzymes have been identified and characterized from parasitoid venom. Here we describe a proteomic analysis of the venom from the endoparasitoid wasp Pteromalus puparum (Hymenoptera: Pteromalidae). Venom resolved by two-dimensional electrophoresis yielded 56 protein spots with major proteins in the pI range 4,7 and molecular mass range of 25,66.2,kDa. The amino acid sequences of the proteins were identified by mass spectrometry. Several venom proteins such as calreticulin, venom acid phosphatase, serine protease, arginine kinase, serine protease homolog, aminotransferase-like venom protein, and heat shock protein 70, were identified in silico based on their amino acid sequences. The full-length cDNAs of calreticulin and arginine kinase were cloned. Calreticulin showed 62% identity with calreticulin in the venom of Cotesia rubecula. Arginine kinase showed a high level of sequence identity (92%) with its counterpart in the venom of Cyphononyx dorsalis. RT-PCR analysis revealed that the transcript levels of calreticulin and arginine kinase were developmentally changed, suggesting a possible correlation with the oviposition process. This study contributes to our appreciation of a parasitoid wasp venom composition. © 2010 Wiley Periodicals, Inc. [source]

Phylogeny, diversification patterns and historical biogeography of euglossine orchid bees (Hymenoptera: Apidae)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2010
SANTIAGO R. RAMÍREZ
The orchid bees constitute a clade of prominent insect pollinators distributed throughout the Neotropical region. Males of all species collect fragrances from natural sources, including flowers, decaying vegetation and fungi, and store them in specialized leg pockets to later expose during courtship display. In addition, orchid bees provide pollination services to a diverse array of Neotropical angiosperms when foraging for food and nesting materials. However, despite their ecological importance, little is known about the evolutionary history of orchid bees. Here, we present a comprehensive molecular phylogenetic analysis based on ,4.0 kb of DNA from four loci [cytochrome oxidase (CO1), elongation factor 1-, (EF1 -,), arginine kinase (ArgK) and RNA polymerase II (Pol-II)] across the entire tribe Euglossini, including all five genera, eight subgenera and 126 of the approximately 200 known species. We investigated lineage diversification using fossil-calibrated molecular clocks and the evolution of morphological traits using disparity-through-time plots. In addition, we inferred past biogeographical events by implementing model-based likelihood methods. Our dataset supports a new view on generic relationships and indicates that the cleptoparasitic genus Exaerete is sister to the remaining orchid bee genera. Our divergence time estimates indicate that extant orchid bee lineages shared a most recent common ancestor at 27,42 Mya. In addition, our analysis of morphology shows that tongue length and body size experienced rapid disparity bursts that coincide with the origin of diverse genera (Euglossa and Eufriesea). Finally, our analysis of historical biogeography indicates that early diversification episodes shared a history on both sides of Mesoamerica, where orchid bees dispersed across the Caribbean, and through a Panamanian connection, thus reinforcing the hypothesis that recent geological events (e.g. the formation of the isthmus of Panama) contributed to the diversification of the rich Neotropical biota. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 552,572. [source]

A comprehensive phylogeny of the bumble bees (Bombus)

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2007
S. A. CAMERON
Bumble bees (Bombus Latreille) occupy a wide diversity of habitats, from alpine meadows to lowland tropical forest, yet they appear to be similar in morphology throughout their range, suggesting that behavioural adaptations play a more important role in colonizing diverse habitats. Notwithstanding their structural homogeneity, bumble bees exhibit striking inter- and intraspecific variation in colour pattern, purportedly the outcome of mimetic evolution. A robust phylogeny of Bombus would provide the framework for elucidating the history of their wide biogeographical distribution and the evolution of behavioural and morphological adaptations, including colour pattern. However, morphological studies of bumble bees have discovered too few phylogenetically informative characters to reconstruct a robust phylogeny. Using DNA sequence data, we report the first nearly complete species phylogeny of bumble bees, including most of the 250 known species from the 38 currently recognized subgenera. Bayesian analysis of nuclear (opsin, EF-1,, arginine kinase, PEPCK) and mitochondrial (16S) sequences results in a highly resolved and strongly supported phylogeny from base to tips, with clear-cut support for monophyly of most of the conventional morphology-based subgenera. Most subgenera fall into two distinct clades (short-faced and long-faced) associated broadly with differences in head morphology. Within the short-faced clade is a diverse New World clade, which includes nearly one-quarter of the currently recognized subgenera, many of which are restricted to higher elevations of Central and South America. The comprehensive phylogeny provides a firm foundation for reclassification and for evaluating character evolution in the bumble bees. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 161,188. [source]