Sandbox Reserved 1068: Difference between revisions

Line 13:

[[Image:Capture.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 16923875</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a"/>. The overall molecular structure consist of a polypeptide of 450 residues that forms <scene name='69/694235/Alpha_helics/2'>one large single domain</scene> 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 <ref name="3a"/>. One side of the groove is formed by β21, C-terminal helix, and α11 while the other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop (Figure 2)<ref name="3a"/>. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Figure 2) <ref name="3a">PMID:16923875</ref>.

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 16923875</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a"/>. The overall molecular structure consist of a polypeptide of 450 residues that forms <scene name='69/694235/Alpha_helics/2'>one large single domain</scene> 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 β sheets </scene>folded into a twisted beta-sandwich. The protein's core is then surrounded by <scene name='69/694235/Beta_sheets/4'>10 α 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 <ref name="3a"/>. One side of the groove is formed by β21, C-terminal helix, and α11 while the other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop (Figure 2)<ref name="3a"/>. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Figure 2) <ref name="3a">PMID:16923875</ref>.

For further structural and sequence information see [http://www.uniprot.org/uniprot/P9WFX1].

Line 48:

[[Image:IS2.png|500 px|center|thumb|'''Figure 7''': Isochorismate synthase activity <ref name="8a"/>.]]

'''~~chorismate~~ mutase (CM)'''

'''Chorismate mutase (CM)'''

A magnesium ion in the active site orients the C1 carboxyl group of chorismate (Figure 8). A lysine residue then serves as a general base for the activation of a water molecule to attack at C2. The catalytic mechanism for conversion of isochorismate to salicylate by MbtI is a sigmatropic, pericyclic mechanism that is pH-dependent. Chromate mutase activity is only observed in the absence of magnesium ion in the active site while salicylate synthase activity is depended on magnesium ion. The active site of MbtI is altered by the removal of the magnesium cofactor causing chromate mutase activity. MbtI has differing binding modes for chromate that leads to different substrate conformations/transition states and resulting in different products.

Sandbox Reserved 1068: Difference between revisions

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 13: / Line 13: @@
 [[Image:Capture.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 16923875</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a"/>. The overall molecular structure consist of a polypeptide of 450 residues that forms <scene name='69/694235/Alpha_helics/2'>one large single domain</scene> 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 <ref name="3a"/>. One side of the groove is formed by β21, C-terminal helix, and α11 while the other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop (Figure 2)<ref name="3a"/>. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Figure 2) <ref name="3a">PMID:16923875</ref>.
+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 16923875</ref>. There are no significant structural changes between the four monomers excepts from the localized differences in the active site <ref name= "3a"/>. The overall molecular structure consist of a polypeptide of 450 residues that forms <scene name='69/694235/Alpha_helics/2'>one large single domain</scene> 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 β sheets </scene>folded into a twisted beta-sandwich. The protein's core is then surrounded by <scene name='69/694235/Beta_sheets/4'>10 α 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 <ref name="3a"/>. One side of the groove is formed by β21, C-terminal helix, and α11 while the other side of the groove is formed by β16-17 loop, helix α7, and β15-α6 loop (Figure 2)<ref name="3a"/>. The β19-20 and β12-13 loops make up the bottom of the active side cleft (Figure 2) <ref name="3a">PMID:16923875</ref>.
 For further structural and sequence information see [http://www.uniprot.org/uniprot/P9WFX1].
@@ Line 48: / Line 48: @@
 [[Image:IS2.png|500 px|center|thumb|'''Figure 7''': Isochorismate synthase activity <ref name="8a"/>.]]
-'''chorismate mutase (CM)'''
+'''Chorismate mutase (CM)'''
 A magnesium ion in the active site orients the C1 carboxyl group of chorismate (Figure 8). A lysine residue then serves as a general base for the activation of a water molecule to attack at C2. The catalytic mechanism for conversion of isochorismate to salicylate by MbtI is a sigmatropic, pericyclic mechanism that is pH-dependent. Chromate mutase activity is only observed in the absence of magnesium ion in the active site while salicylate synthase activity is depended on magnesium ion. The active site of MbtI is altered by the removal of the magnesium cofactor causing chromate mutase activity. MbtI has differing binding modes for chromate that leads to different substrate conformations/transition states and resulting in different products.