PDBsum entry 1aaz

Electron transport

PDB id: 1aaz

Contents

Protein chains

87 a.a. *

Metals

_CD ×2

Waters ×666

* Residue conservation analysis

PDB id:

1aaz

Name:

Electron transport

Title:

The structure of oxidized bacteriophage t4 glutaredoxin (thioredoxin)

Structure:

Glutaredoxin. Chain: a, b. Engineered: yes

Source:

Enterobacteria phage t4. Organism_taxid: 10665

Resolution:

2.00Å R-factor: 0.210

Authors:

H.Eklund,M.Ingelman,B.-O.Soderberg,T.Uhlin,P.Nordlund,M.Nikkola, U.Sonnerstam,T.Joelson,K.Petratos

Key ref:

H.Eklund et al. (1992). Structure of oxidized bacteriophage T4 glutaredoxin (thioredoxin). Refinement of native and mutant proteins. J Mol Biol, 228, 596-618. PubMed id: 1453466 DOI: 10.1016/0022-2836(92)90844-A

Date:

24-Apr-92 Release date: 31-Oct-93

Protein chains

P00276  (GLRX_BPT4) -  Glutaredoxin from Enterobacteria phage T4

Seq: 87 a.a.

Struc: 87 a.a.

DOI no: 10.1016/0022-2836(92)90844-A

J Mol Biol 228:596-618 (1992)

PubMed id: 1453466

Structure of oxidized bacteriophage T4 glutaredoxin (thioredoxin). Refinement of native and mutant proteins.

H.Eklund, M.Ingelman, B.O.Söderberg, T.Uhlin, P.Nordlund, M.Nikkola, U.Sonnerstam, T.Joelson, K.Petratos.

ABSTRACT

The structure of wild-type bacteriophage T4 glutaredoxin (earlier called thioredoxin) in its oxidized form has been refined in a monoclinic crystal form at 2.0 A resolution to a crystallographic R-factor of 0.209. A mutant T4 glutaredoxin gives orthorhombic crystals of better quality. The structure of this mutant has been solved by molecular replacement methods and refined at 1.45 A to an R-value of 0.175. In this mutant glutaredoxin, the active site residues Val15 and Tyr16 have been substituted by Gly and Pro, respectively, to mimic that of Escherichia coli thioredoxin. The main-chain conformation of the wild-type protein is similar in the two independently determined molecules in the asymmetric unit of the monoclinic crystals. On the other hand, side-chain conformations differ considerably between the two molecules due to heterologous packing interactions in the crystals. The structure of the mutant protein is very similar to the wild-type protein, except at mutated positions and at parts involved in crystal contacts. The active site disulfide bridge between Cys14 and Cys17 is located at the first turn of helix alpha 1. The torsion angles of these residues are similar to those of Escherichia coli thioredoxin. The torsion angle around the S-S bond is smaller than that normally observed for disulfides: 58 degrees, 67 degrees and 67 degrees for wild-type glutaredoxin molecule A and B and mutant glutaredoxin, respectively. Each sulfur atom of the disulfide cysteines in T4 glutaredoxin forms a hydrogen bond to one main-chain nitrogen atom. The active site is shielded from solvent on one side by the beta-carbon atoms of the cysteine residues plus side-chains of residues 7, 9, 21 and 33. From the opposite side, there is a cleft where the sulfur atom of Cys14 is accessible and can be attacked by a nucleophilic thiolate ion in the initial step of the reduction reaction.

Selected figure(s)

Figure 4.
Figure 4. Electon density maps of mutant glutaredoxi. The electron density 2(F,j -IF,1 contoured at la for (a) a normal tyrosine Tyr7) and (b) Tyr85 for which the elecron density map indicates 2 conformations, (c) for a normal leucine (Leu85) and (d) the ensity for Leu55 indicating 2 conformations. Both conformations have been treated as haf occupied and no attempts hae ben made to refine the occupancies of the individual conformations.

Figure 7.
Figure 7. Hydrogen bonding scheme. Schematic drawing of the main-chain hydrogen bonding in T4 gluta- redoxin. According to normal conventions, we have assigned a hydrogen bond whn donor and acceptor atoms are closer than 3.3 A.

The above figures are reprinted by permission from Elsevier: J Mol Biol (1992, 228, 596-618) copyright 1992.

Figures were selected by an automated process.