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.


1l4f

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1l4f.gif|left|200px]]
+
{{Seed}}
 +
[[Image:1l4f.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1l4f| PDB=1l4f | SCENE= }}
{{STRUCTURE_1l4f| PDB=1l4f | SCENE= }}
-
'''The crystal structure of CobT complexed with 4,5-dimethyl-1,2-phenylenediamine and nicotinate mononucleotide'''
+
===The crystal structure of CobT complexed with 4,5-dimethyl-1,2-phenylenediamine and nicotinate mononucleotide===
-
==Overview==
+
<!--
-
The evolution of biosynthetic pathways is difficult to reconstruct in hindsight; however, the structures of the enzymes that are involved may provide insight into their development. One enzyme in the cobalamin biosynthetic pathway that appears to have evolved from a protein with different function is L-threonine-O-3-phosphate decarboxylase (CobD) from Salmonella enterica, which is structurally similar to histidinol phosphate aminotransferase [Cheong, C. G., Bauer, C. B., Brushaber, K. R., Escalante-Semerena, J. C., and Rayment, I. (2002) Biochemistry 41, 4798-4808]. This enzyme is responsible for synthesizing (R)-1-amino-2-propanol phosphate which is the precursor for the linkage between the nucleotide loop and the corrin ring in cobalamin. To understand the relationship between this decarboxylase and the aspartate aminotransferase family to which it belongs, the structures of CobD in its apo state, the apo state complexed with the substrate, and its product external aldimine complex have been determined at 1.46, 1.8, and 1.8 A resolution, respectively. These structures show that the enzyme steers the breakdown of the external aldimine toward decarboxylation instead of amino transfer by positioning the carboxylate moiety of the substrate out of the plane of the pyridoxal ring and by placing the alpha-hydrogen out of reach of the catalytic base provided by the lysine that forms the internal aldimine. It would appear that CobD evolved from a primordial PLP-dependent aminotransferase, where the selection was based on similarities between the stereochemical properties of the substrates rather than preservation of the fate of the external aldimine. These structures provide a sequence signature for distinguishing between L-threonine-O-3-phosphate decarboxylase and histidinol phosphate aminotransferases, many of which appear to have been misannotated.
+
The line below this paragraph, {{ABSTRACT_PUBMED_12119022}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 12119022 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_12119022}}
==About this Structure==
==About this Structure==
Line 31: Line 35:
[[Category: Nicotinate mononucleotide]]
[[Category: Nicotinate mononucleotide]]
[[Category: Phosphoribosyltransferase]]
[[Category: Phosphoribosyltransferase]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 23:31:51 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jul 2 11:41:01 2008''

Revision as of 08:41, 2 July 2008

Image:1l4f.png

Template:STRUCTURE 1l4f

The crystal structure of CobT complexed with 4,5-dimethyl-1,2-phenylenediamine and nicotinate mononucleotide

Template:ABSTRACT PUBMED 12119022

About this Structure

1L4F is a Single protein structure of sequence from Salmonella enterica. Full crystallographic information is available from OCA.

Reference

Structural studies of the L-threonine-O-3-phosphate decarboxylase (CobD) enzyme from Salmonella enterica: the apo, substrate, and product-aldimine complexes., Cheong CG, Escalante-Semerena JC, Rayment I, Biochemistry. 2002 Jul 23;41(29):9079-89. PMID:12119022

Page seeded by OCA on Wed Jul 2 11:41:01 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1l4f"
Personal tools