PDBsum entry 1v7y

Lyase

PDB id: 1v7y

Contents

Protein chains

248 a.a. *

Ligands

SO4 ×2

Waters ×87

* Residue conservation analysis

PDB id:

1v7y

Name:

Lyase

Title:

Crystal structure of tryptophan synthase alpha-subunit from escherichia coli at room temperature

Structure:

Tryptophan synthase alpha chain. Chain: a, b. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.50Å R-factor: 0.218 R-free: 0.271

Authors:

K.Nishio,Y.Morimoto,M.Ishizuka,K.Ogasahara,K.Yutani,T.Tsukihara,Riken Structural Genomics/proteomics Initiative (Rsgi)

Key ref:

K.Nishio et al. (2005). Conformational changes in the alpha-subunit coupled to binding of the beta 2-subunit of tryptophan synthase from Escherichia coli: crystal structure of the tryptophan synthase alpha-subunit alone. Biochemistry, 44, 1184-1192. PubMed id: 15667212 DOI: 10.1021/bi047927m

Date:

25-Dec-03 Release date: 15-Feb-05

Protein chains

P0A877  (TRPA_ECOLI) -  Tryptophan synthase alpha chain from Escherichia coli (strain K12)

Seq: 268 a.a.

Struc: 248 a.a.

Enzyme reactions

• Enzyme class: E.C.4.2.1.20 - tryptophan synthase.
• Pathway: Tryptophan Biosynthesis
• Reaction: (1S,2R)-1-C-(indol-3-yl)glycerol 3-phosphate + L-serine = D-glyceraldehyde 3-phosphate + L-tryptophan + H2O
• Cofactor: Pyridoxal 5'-phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1021/bi047927m

Biochemistry 44:1184-1192 (2005)

PubMed id: 15667212

Conformational changes in the alpha-subunit coupled to binding of the beta 2-subunit of tryptophan synthase from Escherichia coli: crystal structure of the tryptophan synthase alpha-subunit alone.

K.Nishio, Y.Morimoto, M.Ishizuka, K.Ogasahara, T.Tsukihara, K.Yutani.

ABSTRACT

When the tryptophan synthase alpha- and beta(2)-subunits combine to form the alpha(2)beta(2)-complex, the enzymatic activity of each subunit is stimulated by 1-2 orders of magnitude. To elucidate the structural basis of this mutual activation, it is necessary to determine the structures of the alpha- and beta-subunits alone and together with the alpha(2)beta(2)-complex. The crystal structures of the tryptophan synthase alpha(2)beta(2)-complex from Salmonella typhimurium (Stalpha(2)beta(2)-complex) have already been reported. However, the structures of the subunit alone from mesophiles have not yet been determined. The structure of the tryptophan synthase alpha-subunit alone from Escherichia coli (Ecalpha-subunit) was determined by an X-ray crystallographic analysis at 2.3 A, which is the first report on the subunits alone from the mesophiles. The biggest difference between the structures of the Ecalpha-subunit alone and the alpha-subunit in the Stalpha(2)beta(2)-complex (Stalpha-subunit) was as follows. Helix 2' in the Stalpha-subunit, including an active site residue (Asp60), was changed to a flexible loop in the Ecalpha-subunit alone. The conversion of the helix to a loop resulted in the collapse of the correct active site conformation. This region is also an important part for the mutual activation in the Stalpha(2)beta(2)-complex and interaction with the beta-subunit. These results suggest that the formation of helix 2'that is essential for the stimulation of the enzymatic activity of the alpha-subunit is constructed by the induced-fit mode involved in conformational changes upon interaction between the alpha- and beta-subunits. This also confirms the prediction of the conformational changes based on the thermodynamic analysis for the association between the alpha- and beta-subunits.