User:Michael Adams/Sandbox 1: Difference between revisions

== Structural Highlights ==

The structure of arginine kinase is mainly α-helical and contains an N-terminal region <ref>PMID:9671698</ref>. However, when compared to creatine kinase, arginine kinase is not terminated with a pair of proline-glycine. Proline typically restricts change in conformation and is the amino acid that terminates helices, while glycine is associated with flexibility.  On the C-terminal end, there are eight-stranded antiparallel β-sheets with seven α-helices flanking them <ref>PMID:9671698</ref>.  

The small domain specificity loop forms a “specificity” pocket surrounding the methyl substituent of the guanidinium group that is unique to creatine substrates.  In this region, five residues differ between arginine and creatine kinases: 312, 314, 315, 317, and 319 <ref>Newsholme, E. A., Beis, I., Leech, A. R., & Zammit, V. A. (1978). The role of creatine

kinase and arginine kinase in muscle. Biochemical Journal, 172(3), 533–537</ref>. Within each arginine kinase, there is typically a Mg+2 ion adjacent to the antiparallel β-sheet <ref>PMID:9671698</ref>. Typically two arginine kinase structures mirror each other and form a hole like structure in between the two.  However, when a substrate is in the binding site, the active site remains unchanged and does not change in conformation <ref>PMID:9671698</ref>.  

& Flawia, M. M. (2000) Trypanosoma cruzi arginine kinase characterization and

cloning., J. Biol.Chem. 275, 1495-1501.</ref>.  

Arginine Kinase is a phosphokinase - a kinase used in the catalyzation of phosphagens and adenosine diphosphate (ADP) into adenosine triphosphate (ATP). Phosphagens act as a storage form of phosphate (Nω-phospho-L-arginine) that can be catalyzed into an energy source (ATP) when needed <ref>http://www.jbc.org/content/275/2/1495.full.pdf</ref>. The arginine kinase is a lock and key catalyst that holds ADP and phosphoarginine in place and catalyzes the transfer of inorganic phosphate on phosphoarginine to ADP and forms of arginine and ATP <ref>DOI 10.1110/ps.03428304</ref>.

== Application to the Animal Kingdom ==  

Drosophila Melanogaster." Www.onlinelibrary.wiley.com. Laboratory of

Developmental Biology, Swiss Federal Institute of Technology, Zurich, 21 June 1973. Web. 12 Nov. 2015</ref>

Arginine Kinase (AK) is represented by a single gene and the sequence or partial sequence is available from Drosophila, Limulus, lobster, shrimp, and abalone <ref>Wang, Yu-mei E., Pia Esbensen, and David Bentley. "Arginine Kinase Expression and

Localization in Growth Cone Migration." The Journal of Neuroscience 18.3