User:Michael Adams/Sandbox 1: Difference between revisions
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== Structural highlights == | == Structural highlights == | ||
The structure of arginine kinase is mainly α-helical and contains an N-terminal region (Figure 1b). 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 (Figure 1). | The structure of arginine kinase is mainly α-helical and contains an N-terminal region (Figure 1b). 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 (Figure 1). | ||
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> | 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>PMID: PMC1185728</ref>. Within each arginine kinase, there is typically a Mg+2 ion adjacent to the antiparallel β-sheet (Figure 1b). 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 (Figure 1a). | ||
== Function == | == Function == | ||
Arginine Kinase is part of a class of kinases that regulates ATP levels in the body to help maintain homeostasis. It creates a sort of storage option for ATP. It is the most common phosphokinase (PK) in invertebrates. The most common PK in vertebrates is Creatine Kinase (Pereira et al, 2000). | Arginine Kinase is part of a class of kinases that regulates ATP levels in the body to help maintain homeostasis. It creates a sort of storage option for ATP. It is the most common phosphokinase (PK) in invertebrates. The most common PK in vertebrates is Creatine Kinase (Pereira et al, 2000). | ||
