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.
1beu
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1beu.gif|left|200px]] | [[Image:1beu.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1beu", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1beu| PDB=1beu | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''TRP SYNTHASE (D60N-IPP-SER) WITH K+''' | '''TRP SYNTHASE (D60N-IPP-SER) WITH K+''' | ||
| Line 30: | Line 27: | ||
[[Category: Mozzarelli, A.]] | [[Category: Mozzarelli, A.]] | ||
[[Category: Rhee, S.]] | [[Category: Rhee, S.]] | ||
| - | [[Category: | + | [[Category: Carbon-oxygen lyase]] |
| - | [[Category: | + | [[Category: Indole-3-propanol phosphate in a-subunit]] |
| - | [[Category: | + | [[Category: L-serine in b-subunit]] |
| - | [[Category: | + | [[Category: Mutation d60n in a-subunit]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 11:25:33 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 08:25, 2 May 2008
TRP SYNTHASE (D60N-IPP-SER) WITH K+
Overview
We have investigated the role of Asp60 of the alpha-subunit in allosteric communication between the tryptophan synthase alpha- and beta-subunits. Crystallographic and microspectrophotometric studies have been carried out on a mutant (alpha D60N) tryptophan synthase alpha 2 beta 2 complex which has no observable alpha-activity, but has substantial beta-activity. Single-crystal polarized absorption spectra indicate that the external aldimine is the predominant L-serine intermediate and that the amount of the intermediate formed is independent of pH, monovalent cations, and allosteric effectors. The three-dimensional structure is reported for this mutant enzyme complexed with indole 3-propanol phosphate bound to the alpha-site and L-serine bound to the beta-site (alpha D60N-IPP-Ser), and this structure is compared with that of the unliganded mutant enzyme (alpha D60N). In the complex, L-serine forms a stable external aldimine with the pyridoxal phosphate coenzyme at the active site of the beta-subunit. The conformation of the unliganded mutant is almost identical to that of the wild type enzyme. However, the structure of the mutant complexed with IPP and serine exhibits ligand-induced conformational changes much smaller than those observed previously for another mutant enzyme in the presence of the same ligands (beta K87T-IPP-Ser) [Rhee, S., Parris, K. D., Hyde, C. C., Ahmed, S. A., Miles, E. W., and Davies, D. R. (1997) Biochemistry 36, 7664-7680]. The alpha D60N-IPP-Ser alpha 2 beta 2 complex does not undergo the following ligand-induced conformational changes: (1) the closure of the alpha-subunit loop 6 (residues 178-191), (2) the movement of the mobile subdomain (residues 93-189) of the beta-subunit, and (3) the rotation of the alpha-subunit relative to the beta-subunit. These observations show that alpha Asp60 plays important roles in the closure of loop 6 and in allosteric communication between the alpha- and beta-subunits.
About this Structure
1BEU is a Protein complex structure of sequences from Salmonella typhimurium. Full crystallographic information is available from OCA.
Reference
Cryocrystallography and microspectrophotometry of a mutant (alpha D60N) tryptophan synthase alpha 2 beta 2 complex reveals allosteric roles of alpha Asp60., Rhee S, Miles EW, Mozzarelli A, Davies DR, Biochemistry. 1998 Jul 28;37(30):10653-9. PMID:9692955 Page seeded by OCA on Fri May 2 11:25:33 2008
