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<Structure load='1ake' size='500' frame='true' align='right' caption='Adenylate Kinase' scene='Insert optional scene name here' />
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==Adenylate Kinase==
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<scene name='Sandbox_33/1ake/1'>Adenylate kinase</scene> (also known as 1AKE) is an enzyme that performs a reaction that quickly converts ATP to ADP. Adenylate Kinase thus plays an important role in cellular metabolism. The images of Adenylate Kinase in this sandbox are from Yersinia Pestis.
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==Secondary Structure==
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The <scene name='Sandbox_33/Secondary_structure_colored/2'>secondary structure</scene> of adenylate kinase consists of 214 amino acids which form 12 alpha helices and 7 beta sheets. The helices in this image are displayed in pink and the anti-parallel beta sheets are shown in purple. The secondary structure is held together by <scene name='Sandbox_33/Hbond/1'>hydrogen bonding</scene>, which is depicted by black lines.
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==Hydrophobic and Hydrophilic Residues==
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Hen Egg-White Lysozyme
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In aqueous, physiological environments the <scene name='Sandbox_33/Stickwire_hydrophobic/1'>hydrophobic residues</scene> of adenylate kinase, seen in grey, are buried in the interior of the protein. The hydrophobic residues cluster together in the interior of the protein in order to avoid the exterior aqueous environment. Some hydrophobic residues are found on the exterior of adenylate kinase, but such residues decrease the stability of the protein. So often, hydrophobic residues on the exterior interact with other hydrophobic residues to avoid the stability loss.
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<applet load='1hew' size='400' frame='true' align='right' caption=' This Jmol image allows us to see the general folding pattern of Hen Egg-White Lysozyme (PDBid:1hew).' scene='Sandbox_33/First_look/1'> />
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The <scene name='Sandbox_33/Stickwire_charged/1'>hydrophilic</scene> polar and charged residues, seen in yellow while the hydrophobic residues are grey, are found on the exterior of adenylate kinase. It might be easier to visualize in <scene name='Sandbox_33/Hydrophilic_better/1'>this</scene> depiction of adenylate kinase, where the hydrophilic residues are depicted in red. Hydrophilic residues are on the exterior of the protein because they can interact with the aqueous exterior environment. Hydrophilic residues can exist on the interior of a protein by interacting solely with one another and avoiding interaction with hydrophobic residues. Hydrophilic residues also exist in the interior active site to stabilize hydrophilic portions of the substrate during catalysis.
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==Water==
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=Background=
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The aqueous environment surrounding adenylate kinase causes it to fold in the conformation that it does. The <scene name='Sandbox_33/Waters/1'>water molecules</scene> that surround adenylate kinase in aqueous environments are depicted in blue. The water surrounds the exterior of the protein and interacts with the hydrophilic proteins only. There are also water molecules found in the active site. There are also some water molecules in the open spaces between the backbone. The waters are not found in the interior of the protein, between two residues. <scene name='Sandbox_33/Waters_with_ligand_highlighted/1'>Here</scene> the ligand is highlighted brown in respect to the hydration shell, for better visualization.
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Hen Egg-White Lysozyme is an enzyme that was first described by the Russian scientist P. Laschtchenko in 1909 and its structure was solved for in 1965 by David Phillips via X-ray crystallography (Garrett, & Grisham, 2005). It is a single polymer of 129 residues (14.3kDa in weight) that catalyzes the hydrolysis of the polysaccharide wall of bacterial cells, breaking the β (1-4) linkage between N-acetylmuramic acid (NAM) and N-acetylglucosamine between the D and E sugars. The D and E sugars are the fourth and fifth sugars, respectively, in reference to the six sugars (oligosaccharide), identified by the letters A-F, that function as the ligand and bind to lysozyme. In hens (Gallus gallus), lysozyme is heavily concentrated in the egg white, serving as an anti-biotic as well as a nutrient to the developing eggs <ref>http://www.ncbi.nlm.nih.gov/pubmed/1569548?dopt</ref>.
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Lysozyme is not only found in hen egg-whites but has many homologs that occur in a wide variety of organisms including humans. The gene for lysozyme in hens is expressed in the oviduct and in macrophages, which directly reflects its purposes (i.e. nutrition and defense). The one gene is controlled at the level of transcription by different means for the different locations and resulting functions (Worthington, 2010).
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=Structure=
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==Enzyme Activity==
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===The Hydrophobic Effect===
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There are many levels of organization that contribute to protein stability, the strongest of which being the hydrophobic effect. The reason the hydrophobic effect is so powerful in determination of the overall protein structure is because proteins exist and function in solvents. Since the body is mostly water, regions that are polar like water (hydrophilic regions) will congregate near it, while regions that not polar will repel from it (hydrophobic), will try to distance themselves from water by being isolated towards the inside or orienting towards other hydrophobic groups so that they might stabilize. This is all a result of entropy because it takes more energy for water to surround and stabilize hydrophobic regions (Garrett, & Grisham, 2005).
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===van der Waals Forces===
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The few hydrophobic residues that do exist on the surface are in the active site and a stabilized by van der Waals forces. Van der Waals forces also exist within the enzyme and stabilize the enzyme of its own need while also stabilizing the bound ligand.
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===Primary, Secondary, and Tertiary Structure===
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The primary structure 129 residues of 1hew result in a secondary structure of 5 alpha helices and 5 beta sheets. They are mostly stabilized by hydrogen bonding between secondary elements, nitrogen, oxygen, hydrogen’s on polar particles and water. The tertiary structure of Lysozyme is made up of several bind motifs. An antiparallel β-sheets occurs between a pseudo β -sheet from bases Lys1-Phe3 and Phe38-Thr40. A helix loop helix occurs from Cys80-Leu84, with a loop occurring from Ser85-Ile88 followed by another helix Thr89-Val99. Also, a β-ladder exists from the antiparallel arrangement of 3 β-sheets from Gln41-Thr47, Gly49-Ile55, and Leu56-Arg61. Each other these structures help reduce the strain on the enzyme <ref>http://www.ncbi.nlm.nih.gov/pubmed/1569548?dopt</ref>.
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===Disulfide Linkages===
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Next, we will observe the disulfide bonds, shown as yellow bars with the bases the join noted. They occur between the following Cystine residues: 6 and 127, 30 and 115, 76 and 94, 64 and 80. Give strong support in the enzyme between pieces of the same chain.
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The active site is where the substrate binds to the enzyme to be catalyzed. The ligand binds to the <scene name='Sandbox_33/Ligand_contacts/1'>ligand contacts</scene> (depicted in color) of the protein. There are mostly hydrophilic residues in the active site because water enter the active site. There are also some hydrophobic residues in the active site, which interacts with the hydrophobic portions of the substrate (or more likely, the transition state) to stabilize it during catalysis. There are six <scene name='Sandbox_33/Catalytic_residues/1'>catalytic residues</scene> (which are highlighted in blue while all the ligand contacts are depicted in pink) which help perform the catalysis by forming hydrogen bonds with the substrate to hold it in place for the reaction.
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=Activity=
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==Resources==
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===Functional Preferences===
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http://en.wikipedia.org/wiki/Adenylate_kinase
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The function of lysozyme is optimal under physiological conditions of a pH 6-9 with maximal function observed at pH= 6.2 and temperatures around 37oC. Furthermore, while lysozyme can lyse short saccharides, it is more efficient when cutting 3 repeating NAG-NAM units (Worthington, 2010).
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===Mechanism===
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The active site of Lysozyme has a few key components that are integral parts of its catalytic ability. Glu35 acts as an acid, donating an H+ to the O in the glycosidic bond. Asp52 will covalently catalyze the reaction by binding its carboxyl group to the unstable positive ion. Water then enters the system and a hydroxyl group will add to the sugar of the NAM. Both Glu35 and Asp52 will return to their natural states and will continue as catalysts.
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=References=
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<ref>Worthington, Von. (2010). Lysozyme. Retrieved from http://www.worthington-biochem.com/ly/default.html </ref>
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<ref>Garrett, RH, & Grisham, CM. (2005). Biochemistry:The Third Edition. Belmont, CA: Thomson Brooks/Cole. </ref>
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<references/>
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Current revision

Please do NOT make changes to this Sandbox. Sandboxes 30-60 are reserved for use by Biochemistry 410 & 412 at Messiah College taught by Dr. Hannah Tims during Fall 2012 and Spring 2013.

Adenylate Kinase

Drag the structure with the mouse to rotate

Contents

Adenylate Kinase

(also known as 1AKE) is an enzyme that performs a reaction that quickly converts ATP to ADP. Adenylate Kinase thus plays an important role in cellular metabolism. The images of Adenylate Kinase in this sandbox are from Yersinia Pestis.

Secondary Structure

The of adenylate kinase consists of 214 amino acids which form 12 alpha helices and 7 beta sheets. The helices in this image are displayed in pink and the anti-parallel beta sheets are shown in purple. The secondary structure is held together by , which is depicted by black lines.

Hydrophobic and Hydrophilic Residues

In aqueous, physiological environments the of adenylate kinase, seen in grey, are buried in the interior of the protein. The hydrophobic residues cluster together in the interior of the protein in order to avoid the exterior aqueous environment. Some hydrophobic residues are found on the exterior of adenylate kinase, but such residues decrease the stability of the protein. So often, hydrophobic residues on the exterior interact with other hydrophobic residues to avoid the stability loss.

The polar and charged residues, seen in yellow while the hydrophobic residues are grey, are found on the exterior of adenylate kinase. It might be easier to visualize in depiction of adenylate kinase, where the hydrophilic residues are depicted in red. Hydrophilic residues are on the exterior of the protein because they can interact with the aqueous exterior environment. Hydrophilic residues can exist on the interior of a protein by interacting solely with one another and avoiding interaction with hydrophobic residues. Hydrophilic residues also exist in the interior active site to stabilize hydrophilic portions of the substrate during catalysis.

Water

The aqueous environment surrounding adenylate kinase causes it to fold in the conformation that it does. The that surround adenylate kinase in aqueous environments are depicted in blue. The water surrounds the exterior of the protein and interacts with the hydrophilic proteins only. There are also water molecules found in the active site. There are also some water molecules in the open spaces between the backbone. The waters are not found in the interior of the protein, between two residues. the ligand is highlighted brown in respect to the hydration shell, for better visualization.

Enzyme Activity

The active site is where the substrate binds to the enzyme to be catalyzed. The ligand binds to the (depicted in color) of the protein. There are mostly hydrophilic residues in the active site because water enter the active site. There are also some hydrophobic residues in the active site, which interacts with the hydrophobic portions of the substrate (or more likely, the transition state) to stabilize it during catalysis. There are six (which are highlighted in blue while all the ligand contacts are depicted in pink) which help perform the catalysis by forming hydrogen bonds with the substrate to hold it in place for the reaction.

Resources

http://en.wikipedia.org/wiki/Adenylate_kinase

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