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.


1ngs

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1ngs.gif|left|200px]]
+
{{Seed}}
 +
[[Image:1ngs.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1ngs| PDB=1ngs | SCENE= }}
{{STRUCTURE_1ngs| PDB=1ngs | SCENE= }}
-
'''COMPLEX OF TRANSKETOLASE WITH THIAMIN DIPHOSPHATE, CA2+ AND ACCEPTOR SUBSTRATE ERYTHROSE-4-PHOSPHATE'''
+
===COMPLEX OF TRANSKETOLASE WITH THIAMIN DIPHOSPHATE, CA2+ AND ACCEPTOR SUBSTRATE ERYTHROSE-4-PHOSPHATE===
-
==Overview==
+
<!--
-
The three-dimensional structure of the quaternary complex of Saccharomyces cerevisiae transketolase, thiamin diphosphate, Ca2+, and the acceptor substrate erythrose-4-phosphate has been determined to 2.4 A resolution by protein crystallographic methods. Erythrose-4-phosphate was generated by enzymatic cleavage of fructose-6-phosphate. The overall structure of the enzyme in the quaternary complex is very similar to the structure of the holoenzyme; no large conformational changes upon substrate binding were found. The substrate binds in a deep cleft between the two subunits. The phosphate group of the substrate interacts with the side chains of the conserved residues Arg359, Arg528, His469, and Ser386 at the entrance of this cleft. The aldehyde moiety of the sugar phosphate is located in the vicinity of the C-2 carbon atom of the thiazolium ring of the cofactor. The aldehyde oxygen forms hydrogen bonds to the side chains of the residues His30 and His263. One of the hydroxyl groups of the sugar phosphate forms a hydrogen bond to the side chain of Asp477. The preference of the enzyme for donor substrates with D-threo configuration at the C-3 and C-4 positions and for alpha-hydroxylated acceptor substrates can be understood from the pattern of hydrogen bonds between enzyme and substrate. Amino acid replacements by site-directed mutagenesis of residues Arg359, Arg528, and His469 at the phosphate binding site yield mutant enzymes with considerable residual catalytic activity but increased Km values for the donor and in particular acceptor substrate, consistent with a role for these residues in phosphate binding. Replacement of Asp477 by alanine results in a mutant enzyme impaired in catalytic activity and with increased Km values for donor and acceptor substrates. These findings suggest a role for this amino acid in substrate binding and catalysis.
+
The line below this paragraph, {{ABSTRACT_PUBMED_8999873}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 8999873 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_8999873}}
==About this Structure==
==About this Structure==
Line 30: Line 34:
[[Category: Thiamine pyrophosphate]]
[[Category: Thiamine pyrophosphate]]
[[Category: Transferase]]
[[Category: Transferase]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 02:30:50 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 13:26:09 2008''

Revision as of 10:26, 27 July 2008

Image:1ngs.png

Template:STRUCTURE 1ngs

COMPLEX OF TRANSKETOLASE WITH THIAMIN DIPHOSPHATE, CA2+ AND ACCEPTOR SUBSTRATE ERYTHROSE-4-PHOSPHATE

Template:ABSTRACT PUBMED 8999873

About this Structure

1NGS is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.

Reference

Examination of substrate binding in thiamin diphosphate-dependent transketolase by protein crystallography and site-directed mutagenesis., Nilsson U, Meshalkina L, Lindqvist Y, Schneider G, J Biol Chem. 1997 Jan 17;272(3):1864-9. PMID:8999873

Page seeded by OCA on Sun Jul 27 13:26:09 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

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