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.


1iwb

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1iwb.jpg|left|200px]]
+
{{Seed}}
 +
[[Image:1iwb.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1iwb| PDB=1iwb | SCENE= }}
{{STRUCTURE_1iwb| PDB=1iwb | SCENE= }}
-
'''Crystal structure of diol dehydratase'''
+
===Crystal structure of diol dehydratase===
-
==Overview==
+
<!--
-
Substrate binding triggers catalytic radical formation through the cobalt-carbon bond homolysis in coenzyme B12-dependent enzymes. We have determined the crystal structure of the substrate-free form of Klebsiella oxytoca diol dehydratase*cyanocobalamin complex at 1.85 A resolution. The structure contains two units of the heterotrimer consisting of alpha, beta, and gamma subunits. As compared with the structure of its substrate-bound form, the beta subunits are tilted by approximately 3 degrees and cobalamin is also tilted so that pyrrole rings A and D are significantly lifted up toward the substrate-binding site, whereas pyrrole rings B and C are only slightly lifted up. The structure revealed that the potassium ion in the substrate-binding site of the substrate-free enzyme is also heptacoordinated; that is, two oxygen atoms of two water molecules coordinate to it instead of the substrate hydroxyls. A modeling study in which the structures of both the cobalamin moiety and the adenine ring of the coenzyme were superimposed onto those of the enzyme-bound cyanocobalamin and the adenine ring-binding pocket, respectively, demonstrated that the distortions of the Co-C bond in the substrate-free form are already marked but slightly smaller than those in the substrate-bound form. It was thus strongly suggested that the Co-C bond becomes largely activated (labilized) when the coenzyme binds to the apoenzyme even in the absence of substrate and undergoes homolysis through the substrate-induced conformational changes of the enzyme. Kinetic coupling of Co-C bond homolysis with hydrogen abstraction from the substrate shifts the equilibrium to dissociation.
+
The line below this paragraph, {{ABSTRACT_PUBMED_12379103}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 12379103 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_12379103}}
==About this Structure==
==About this Structure==
Line 29: Line 33:
[[Category: Yasuoka, N.]]
[[Category: Yasuoka, N.]]
[[Category: Beta-alpha-barrel]]
[[Category: Beta-alpha-barrel]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 20:30:05 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 14:07:13 2008''

Revision as of 11:07, 1 July 2008

Image:1iwb.png

Template:STRUCTURE 1iwb

Crystal structure of diol dehydratase

Template:ABSTRACT PUBMED 12379103

About this Structure

1IWB is a Protein complex structure of sequences from Klebsiella oxytoca. Full crystallographic information is available from OCA.

Reference

Substrate-induced conformational change of a coenzyme B12-dependent enzyme: crystal structure of the substrate-free form of diol dehydratase., Shibata N, Masuda J, Morimoto Y, Yasuoka N, Toraya T, Biochemistry. 2002 Oct 22;41(42):12607-17. PMID:12379103

Page seeded by OCA on Tue Jul 1 14:07:13 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

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