Sandbox Reserved 1068: Difference between revisions

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==Structure==
==Structure==


[[Image:Active_site_cleft.png|300 px|left|thumb|Figure 2: This shows a single sub unit of MbtI, with the active site cleft located at the lower left hand side of the image.]]
[[Image:Active_site_cleft.png|300 px|left|thumb|'''Figure 2''': Monomeric ribbon diagram of MbtI with active site cleft highlighted with a white circle. Generated from [[3log]] (3a)]]


The crystal asymmetric unit was found to contain <scene name='69/694235/3log/11'> four MbtI molecules</scene>, however crystal packing and size exclusion chromatography data suggest a monomeric enzyme <ref name= "3a">PMID 15342575</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a">PMID 15342575</ref>. The overall molecular structure consist of a polypeptide of 450 residues that forms one large single domain with a similar fold to other chromate-utilizing enzymes <ref name="3a"/>. The core of the protein is formed by <scene name='69/694234/Beta_sheets/1'>21 Beta sheets </scene>folded into a twisted beta-sandwich. The protein's core is then surrounded by <scene name='69/694235/Beta_sheets/4'>10 alpha helices</scene><ref name="3a"/>. The active site was identified by comparison to the product bound forms of Irp9 and TrpE and is situated in a cleft that is about 12Å in length, 10Å deep, and 7Å wide. One side of the groove is formed by β21, C-terminal helix, and α11. The other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Harrison 2006)
The crystal asymmetric unit was found to contain <scene name='69/694235/3log/11'> four MbtI molecules</scene>, however crystal packing and size exclusion chromatography data suggest a monomeric enzyme <ref name= "3a">PMID 15342575</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a">PMID 15342575</ref>. The overall molecular structure consist of a polypeptide of 450 residues that forms one large single domain with a similar fold to other chromate-utilizing enzymes <ref name="3a"/>. The core of the protein is formed by <scene name='69/694234/Beta_sheets/1'>21 Beta sheets </scene>folded into a twisted beta-sandwich. The protein's core is then surrounded by <scene name='69/694235/Beta_sheets/4'>10 alpha helices</scene><ref name="3a"/>. The active site was identified by comparison to the product bound forms of Irp9 and TrpE and is situated in a cleft that is about 12Å in length, 10Å deep, and 7Å wide. One side of the groove is formed by β21, C-terminal helix, and α11. The other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Figure 2)(Harrison 2006)