1dq1

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
(New page: 200px<br /><applet load="1dq1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dq1, resolution 2.15&Aring;" /> '''Calcium;Calcium conc...)
Line 1: Line 1:
-
[[Image:1dq1.gif|left|200px]]<br /><applet load="1dq1" size="450" color="white" frame="true" align="right" spinBox="true"
+
[[Image:1dq1.gif|left|200px]]<br /><applet load="1dq1" size="350" color="white" frame="true" align="right" spinBox="true"
caption="1dq1, resolution 2.15&Aring;" />
caption="1dq1, resolution 2.15&Aring;" />
'''Calcium;Calcium concanavalin A'''<br />
'''Calcium;Calcium concanavalin A'''<br />
==Overview==
==Overview==
-
The reversible binding of manganese and calcium to concanavalin A, determines the carbohydrate binding of the lectin by inducing large, conformational changes. These changes are governed by the isomerization of, a non-proline peptide bond, Ala-207-Asp-208, positioned in a beta-strand, in between the calcium binding site S2 and the carbohydrate, specificity-determining loop. The replacement of calcium by manganese, allowed us to investigate the structures of the carbohydrate binding, locked state and the inactive, unlocked state of concanavalin A, both with, and without metal ions bound. Crystals of unlocked metal-free concanavalin, A convert to the locked form with the binding of two Mn(2+) ions. Removal, of these ions from the crystals traps metal-free concanavalin A in its, locked state, a minority species in solution. The ligation of a metal ion, in S2 to unlocked concanavalin A causes bending of the beta-strand, foregoing the S2 ligand residues Asp-10 and Tyr-12. This bending disrupts, conventional beta-sheet hydrogen bonding and forces the Thr-11 side chain, against the Ala-207-Asp-208 peptide bond. The steric strain exerted by, Thr-11 is presumed to drive the trans-to-cis isomerization. Upon, isomerization, Asp-208 flips into its carbohydrate binding position, and, the conformation of the carbohydrate specificity determining loop changes, dramatically.
+
The reversible binding of manganese and calcium to concanavalin A determines the carbohydrate binding of the lectin by inducing large conformational changes. These changes are governed by the isomerization of a non-proline peptide bond, Ala-207-Asp-208, positioned in a beta-strand in between the calcium binding site S2 and the carbohydrate specificity-determining loop. The replacement of calcium by manganese allowed us to investigate the structures of the carbohydrate binding, locked state and the inactive, unlocked state of concanavalin A, both with and without metal ions bound. Crystals of unlocked metal-free concanavalin A convert to the locked form with the binding of two Mn(2+) ions. Removal of these ions from the crystals traps metal-free concanavalin A in its locked state, a minority species in solution. The ligation of a metal ion in S2 to unlocked concanavalin A causes bending of the beta-strand foregoing the S2 ligand residues Asp-10 and Tyr-12. This bending disrupts conventional beta-sheet hydrogen bonding and forces the Thr-11 side chain against the Ala-207-Asp-208 peptide bond. The steric strain exerted by Thr-11 is presumed to drive the trans-to-cis isomerization. Upon isomerization, Asp-208 flips into its carbohydrate binding position, and the conformation of the carbohydrate specificity determining loop changes dramatically.
==About this Structure==
==About this Structure==
-
1DQ1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1DQ1 OCA].
+
1DQ1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Canavalia_ensiformis Canavalia ensiformis] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1DQ1 OCA].
==Reference==
==Reference==
Line 28: Line 28:
[[Category: transition metal]]
[[Category: transition metal]]
-
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Nov 20 13:29:18 2007''
+
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:19:14 2008''

Revision as of 10:19, 21 February 2008


1dq1, resolution 2.15Å

Drag the structure with the mouse to rotate

Calcium;Calcium concanavalin A

Overview

The reversible binding of manganese and calcium to concanavalin A determines the carbohydrate binding of the lectin by inducing large conformational changes. These changes are governed by the isomerization of a non-proline peptide bond, Ala-207-Asp-208, positioned in a beta-strand in between the calcium binding site S2 and the carbohydrate specificity-determining loop. The replacement of calcium by manganese allowed us to investigate the structures of the carbohydrate binding, locked state and the inactive, unlocked state of concanavalin A, both with and without metal ions bound. Crystals of unlocked metal-free concanavalin A convert to the locked form with the binding of two Mn(2+) ions. Removal of these ions from the crystals traps metal-free concanavalin A in its locked state, a minority species in solution. The ligation of a metal ion in S2 to unlocked concanavalin A causes bending of the beta-strand foregoing the S2 ligand residues Asp-10 and Tyr-12. This bending disrupts conventional beta-sheet hydrogen bonding and forces the Thr-11 side chain against the Ala-207-Asp-208 peptide bond. The steric strain exerted by Thr-11 is presumed to drive the trans-to-cis isomerization. Upon isomerization, Asp-208 flips into its carbohydrate binding position, and the conformation of the carbohydrate specificity determining loop changes dramatically.

About this Structure

1DQ1 is a Single protein structure of sequence from Canavalia ensiformis with as ligand. Full crystallographic information is available from OCA.

Reference

The structural features of concanavalin A governing non-proline peptide isomerization., Bouckaert J, Dewallef Y, Poortmans F, Wyns L, Loris R, J Biol Chem. 2000 Jun 30;275(26):19778-87. PMID:10748006

Page seeded by OCA on Thu Feb 21 12:19:14 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Personal tools