PDBsum entry: 1urh

Transferase

PDB id: 1urh

Contents

Protein chains

263 a.a. *

Ligands

SO3

Waters ×68

* Residue conservation analysis

PDB id:

1urh

Name:

Transferase

Title:

The "rhodanese" fold and catalytic mechanism of 3-mercaptopyruvate sulfotransferases: crystal structure of ssea from escherichia coli

Structure:

3-mercaptopyruvate sulfurtransferase. Chain: a, b. Synonym: ssea, rhodanese-like protein, mst. Engineered: yes. Other_details: residues a186-a189 and b181-b191 are not included in the model.

Source:

Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

2.8Å R-factor: 0.234 R-free: 0.289

Authors:

A.Spallarossa,F.Forlani,A.Carpen,A.Armirotti,S.Pagani, M.Bolognesi,D.Bordo

Key ref:

A.Spallarossa et al. (2004). The "rhodanese" fold and catalytic mechanism of 3-mercaptopyruvate sulfurtransferases: crystal structure of SseA from Escherichia coli. J Mol Biol, 335, 583-593. PubMed id: 14672665 DOI: 10.1016/j.jmb.2003.10.072

Date:

30-Oct-03 Release date: 18-Dec-03

Protein chains

P31142  (THTM_ECOLI) -  3-mercaptopyruvate sulfurtransferase

Seq: 281 a.a.

Struc: 263 a.a.

Enzyme reactions

• Enzyme class: E.C.2.8.1.2 - 3-mercaptopyruvate sulfurtransferase.
• Reaction: 3-mercaptopyruvate + cyanide = pyruvate + thiocyanate
• Cofactor: Zinc

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

 Gene Ontology (GO) functional annotation 

• Cellular component: cytoplasm (1 term)
• Biological process: sulfate transport (1 term)
• Biochemical function: transferase activity (3 terms)

reference

DOI no: 10.1016/j.jmb.2003.10.072

J Mol Biol 335:583-593 (2004)

PubMed id: 14672665

The "rhodanese" fold and catalytic mechanism of 3-mercaptopyruvate sulfurtransferases: crystal structure of SseA from Escherichia coli.

A.Spallarossa, F.Forlani, A.Carpen, A.Armirotti, S.Pagani, M.Bolognesi, D.Bordo.

ABSTRACT

3-Mercaptopyruvate sulfurtransferases (MSTs) catalyze, in vitro, the transfer of a sulfur atom from substrate to cyanide, yielding pyruvate and thiocyanate as products. They display clear structural homology with the protein fold observed in the rhodanese sulfurtransferase family, composed of two structurally related domains. The role of MSTs in vivo, as well as their detailed molecular mechanisms of action have been little investigated. Here, we report the crystal structure of SseA, a MST from Escherichia coli, which is the first MST three-dimensional structure disclosed to date. SseA displays specific structural differences relative to eukaryotic and prokaryotic rhodaneses. In particular, conformational variation of the rhodanese active site loop, hosting the family invariant catalytic Cys residue, may support a new sulfur transfer mechanism involving Cys237 as the nucleophilic species and His66, Arg102 and Asp262 as residues assisting catalysis.

Selected figure(s)

Figure 1.
Figure 1. (a) Stereo view of the superposition of the two SseA molecules in the asymmetric unit. Molecules A and B, displayed as ribbon diagrams, are shown in blue and pink, respectively. Secondary structure elements are labeled following the scheme adopted for the rhodanese fold; a single quote indicates elements of the C-terminal domain. The closed and open conformations adopted by the 61-67 segment in molecules A and B are displayed in red and green, respectively. Active site loops are shown in cyan and the catalytic residue, Cys237, is depicted in ball-and-stick. The portion of aB'-bC' loops which are disordered in both SseA molecules are represented as dotted lines; their position is purely hypothetical. The drawings were prepared with the programs MOLSCRIPT[37.] and Raster3D. [38.] (b) Semi-transparent van der Waals surface representation and C^a trace of SseA chain B, shown in the same orientation as in (a). The Cys237 Sd atom, not included in the calculation of the protein surface, is shown in yellow. The picture was prepared using the program DINO (http://www.bioz.unibas.ch/~xray/dino).

Figure 3.
Figure 3. (a) Stereo view of the electron density map (2F[o] -F[c]) in the active site region of the SseA B molecule, contoured at 1.0s. The extra Sd atom was not included in map calculations to avoid biases. C, N, O and S atoms are shown in grey, blue, red and yellow, respectively. The picture was drawn with the program BOBSCRIPT.[39.] (b) Overlay of the two active site loops (A chain, blue; B chain, pink), highlighting the different conformations achieved by His66 and Asp262 as a consequence of the 61-67 segment shift. Arg178 and a water molecule hydrogen bonded to His66 are also depicted. (c) Structural superposition of SseA and Rhodbov in the neighborhood of the active site. The SseA molecule is shown in blue, Rhobov in green. The catalytic Rhobov residue Cys247, and the SseA Cys237 are represented in ball-and-stick in green and blue, respectively. Sulfur atoms are colored yellow. The 61-67 segment, as observed in SseA molecule A (closed conformation), is displayed in red.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2004, 335, 583-593) copyright 2004.

Figures were selected by an automated process.