This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1upp

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1upp.jpg|left|200px]]
+
{{Seed}}
 +
[[Image:1upp.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1upp| PDB=1upp | SCENE= }}
{{STRUCTURE_1upp| PDB=1upp | SCENE= }}
-
'''SPINACH RUBISCO IN COMPLEX WITH 2-CARBOXYARABINITOL 2 BISPHOSPHATE AND CALCIUM.'''
+
===SPINACH RUBISCO IN COMPLEX WITH 2-CARBOXYARABINITOL 2 BISPHOSPHATE AND CALCIUM.===
-
==Overview==
+
<!--
-
Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) catalyses CO(2) assimilation in biology. A prerequisite for catalysis is an activation process, whereby an active site lysine is selectively carbamylated. The carbamyl group is then stablised by a metal ion, which in vivo is Mg(2+). Other divalent metal ions can replace Mg(2+) as activators in vitro, but the nature of the metal ion strongly influences the catalytic activity of the enzyme and has a differential effect on the ratio of the carboxylation reaction and the competing oxygenation reaction. Biochemical studies show that calcium promotes carbamylation but not catalysis. To investigate the role of the metal in catalysis, we have determined two structures of the enzyme complexed with Ca(2+) and the transition state analogue 2-carboxy-D-arbinitol-1,5-bisphosphate (2CABP). One of the complexes was prepared by soaking 2CABP into crystals of the enzyme-Ca(2+)-product complex, while the other was obtained by cocrystallising the enzyme with calcium and 2CABP under activating conditions. The two crystals belong to different space groups, and one was merohedrally twinned. Both complexes show very similar three-dimensional features. The enzyme is carbamylated at Lys201, and requisite loops close over the bound ligands in the active site, shielding them from the solvent in a manner similar to the corresponding complex with Mg(2+). However, there are subtle differences that could explain the particular role of Ca(2+) in these processes. The larger radius of the calcium ion and its reduced Lewis-acid character causes a significant increase in the required proton hop distance between the C3 proton and the carbamate on Lys201 in the calcium complex. This alone could explain the inability of calcium to sustain catalysis in Rubisco. Similar effects are also expected on subsequent proton transfer steps in the catalytic cycle. Here we also discuss the effect of metal substitution on the dynamics of the ligands around the metal ion.
+
The line below this paragraph, {{ABSTRACT_PUBMED_14596800}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 14596800 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_14596800}}
==About this Structure==
==About this Structure==
Line 31: Line 35:
[[Category: Oxidoreductase]]
[[Category: Oxidoreductase]]
[[Category: Photosynthesis]]
[[Category: Photosynthesis]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 11:32:40 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 23:45:42 2008''

Revision as of 20:45, 28 July 2008

Image:1upp.png

Template:STRUCTURE 1upp

SPINACH RUBISCO IN COMPLEX WITH 2-CARBOXYARABINITOL 2 BISPHOSPHATE AND CALCIUM.

Template:ABSTRACT PUBMED 14596800

About this Structure

1UPP is a Protein complex structure of sequences from Spinacia oleracea. Full crystallographic information is available from OCA.

Reference

Calcium supports loop closure but not catalysis in Rubisco., Karkehabadi S, Taylor TC, Andersson I, J Mol Biol. 2003 Nov 14;334(1):65-73. PMID:14596800

Page seeded by OCA on Mon Jul 28 23:45:42 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1upp"
Personal tools