User:Michael Adams/Sandbox 1: Difference between revisions
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Developmental Biology, Swiss Federal Institute of Technology, Zurich, 21 June 1973. Web. 12 Nov. 2015</ref>. This is done by the transfer of an N-phosphoryl group from phosphocreatine to ADP. | Developmental Biology, Swiss Federal Institute of Technology, Zurich, 21 June 1973. Web. 12 Nov. 2015</ref>. This is done by the transfer of an N-phosphoryl group from phosphocreatine to ADP. | ||
== Structure == | == Structure == | ||
The structure of <scene name='71/716599/My3/1'>arginine kinase</scene> is mainly α-helical and contains an N-terminal region with a specificity loop for specific substrate binding. (Figure 2). However, when compared to creatine kinase, arginine kinase is not terminated at the N-terminal end with a pair of proline-glycine residues. Typically within creatine kinase, the proline molecules restrict changes in conformation and is the amino acid that terminates helices. The glycine chains are usually associated with flexibility. However, in arginine kinase this is typically not the case. On the C-terminal end, there is an eight-stranded antiparallel <scene name='71/716599/Beta/1'>β-sheet</scene> with seven <scene name='71/716599/Mynewscene/1'>α-helices</scene> flanking the sheet (Figure 1). | The structure of <scene name='71/716599/My3/1'>arginine kinase</scene> is mainly α-helical and contains an N-terminal region with a specificity loop for specific substrate binding. (Figure 2). However, when compared to creatine kinase, arginine kinase is not terminated at the N-terminal end with a pair of proline-glycine residues. Typically within creatine kinase, the proline molecules restrict changes in conformation and is the amino acid that terminates helices. The glycine chains are usually associated with flexibility. However, in arginine kinase this is typically not the case. On the C-terminal end, there is an eight-stranded antiparallel <scene name='71/716599/Beta/1'>β-sheet</scene> with seven <scene name='71/716599/Mynewscene/1'>α-helices</scene> flanking the sheet (Figure 1). Residue 330 is an arginine that appears to play a crucial role in maintaining structural stability. Studies show that a mutation in the residue leads to a steep decline in enzymatic activity <ref>DOI 10.1016/j.ijbiomac.2012.12.015</ref>. | ||
[[Image:F1.large.jpg|left|frame|none|alt=Alt text|Figure 1. Structure of an AK in substrate-bound form]] | [[Image:F1.large.jpg|left|frame|none|alt=Alt text|Figure 1. Structure of an AK in substrate-bound form]] | ||
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[[Image:3M10 bio r 500.jpg|inline|left|frame|none|alt=Alt text|Figure 2. Structure of an AK in an unbound conformation]] | [[Image:3M10 bio r 500.jpg|inline|left|frame|none|alt=Alt text|Figure 2. Structure of an AK in an unbound conformation]] | ||
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 | 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 Mg2+ ion adjacent to the antiparallel β-sheet (Figure 2). Typically two arginine kinase structures mirror each other and form a hole like structure in between the two | kinase and arginine kinase in muscle. Biochemical Journal, 172(3), 533–537.</ref>. Within each arginine kinase, there is typically a Mg2+ ion adjacent to the antiparallel β-sheet (Figure 2). Typically two arginine kinase structures mirror each other and form a hole like structure in between the two (Figure 1). | ||
== Function == | == Function == | ||
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== Application to the Animal Kingdom == | == Application to the Animal Kingdom == | ||
Arginine Kinase is the individual phosphagen kinase that is found in major invertebrates, such as: arthropods, mollusks, and echinoderms. Most recently, an arginine kinase was purified from a house fly <ref name=wallimann1973 />. This gave Wallimann and Eppenberger the initiative to investigate the arginine kinase in Drosophila melanogaster, also known as a fruit fly | Arginine Kinase is the individual phosphagen kinase that is found in major invertebrates, such as: arthropods, mollusks, and echinoderms. Most recently, an arginine kinase was purified from a house fly <ref name=wallimann1973 />. This gave Wallimann and Eppenberger the initiative to investigate the arginine kinase in Drosophila melanogaster, also known as a fruit fly <ref name=wallimann1973 />. Since the genome and genetic development of Drosophila melanogaster is well understood, this allows for any discoveries made to be easily interpreted. Additionally, further discoveries will help better understand the characteristics of arginine kinase corresponding vertebrate enzyme, creatine kinase <ref name=wallimann1973 />. | ||
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 | 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 | ||
