1bpj: Difference between revisions

Revision as of 19:29, 30 June 2008

This article has been automatically seeded. Changes to this page should pertain to the PDB entry only and not to the protein or biomolecule in general.

File:1bpj.png

Template:STRUCTURE 1bpj

THYMIDYLATE SYNTHASE R178T, R179T DOUBLE MUTANTTHYMIDYLATE SYNTHASE R178T, R179T DOUBLE MUTANT

Template:ABSTRACT PUBMED 10653645

About this StructureAbout this Structure

1BPJ is a Single protein structure of sequence from Lactobacillus casei. Full crystallographic information is available from OCA.

ReferenceReference

Energetic contributions of four arginines to phosphate-binding in thymidylate synthase are more than additive and depend on optimization of "effective charge balance"., Morse RJ, Kawase S, Santi DV, Finer-Moore J, Stroud RM, Biochemistry. 2000 Feb 8;39(5):1011-20. PMID:10653645

Page seeded by OCA on Mon Jun 30 19:29:56 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
-[[Image:1bpj.jpg|left|200px]]
+{{Seed}}
+[[Image:1bpj.png|left|200px]]
 <!--
@@ Line 9: / Line 10: @@
 {{STRUCTURE_1bpj|  PDB=1bpj  |  SCENE=  }}
-'''THYMIDYLATE SYNTHASE R178T, R179T DOUBLE MUTANT'''
+===THYMIDYLATE SYNTHASE R178T, R179T DOUBLE MUTANT===
-==Overview==
+<!--
-In thymidylate synthase, four conserved arginines provide two hydrogen bonds each to the oxygens of the phosphate group of the substrate, 2'-deoxyuridine-5'-monophosphate. Of these, R23, R178, and R179 are far removed from the site of methyl transfer and contribute to catalysis solely through binding and orientation of ligands. These arginines can be substituted by other residues, while still retaining more than 1% activity of the wild-type enzyme. We compared the kinetics and determined the crystal structures of dUMP complexes of three of the most active, uncharged single mutants of these arginines, R23I, R178T, and R179T, and of double mutants (R23I, R179T) and (R178T, R179T). The dramatically higher K(m) for R178T compared to the other two single mutants arises from the effects of R178 substitution on the orientation of dUMP; 10-15-fold increases in for R23I and R178T reflect the role of these residues in stabilizing the closed conformation of TS in ternary complexes. The free energy for productive dUMP binding, DeltaG(S), increases by at least 1 kcal/mol for each mutant, even when dUMP orientation and mobility in the crystal structure is the same as in wild-type enzyme. Thus, the four arginines do not contribute excess positive charge to the PO(4)(-2) binding site; rather, they ideally complement the charge and geometry of the phosphate moiety. More-than-additive increases in DeltaG(S) seen in the double mutants are consistent with quadratic increases in DeltaG(S) predicted for deviations from ideal electrostatic interactions and may also reflect cooperative binding of the arginines to the phosphate oxygens.
+The line below this paragraph, {{ABSTRACT_PUBMED_10653645}}, adds the Publication Abstract to the page
+(as it appears on PubMed at http://www.pubmed.gov), where 10653645 is the PubMed ID number.
+-->
+{{ABSTRACT_PUBMED_10653645}}
 ==About this Structure==
@@ Line 29: / Line 33: @@
 [[Category: Nucleotide biosynthesis]]
 [[Category: Transferase]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 11:48:07 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 19:29:56 2008''