PDBsum entry 5hr0

Oxidoreductase

PDB id: 5hr0

Contents

Protein chains

108 a.a.

Metals

_CU ×4

Waters ×170

PDB id:

5hr0

Name:

Oxidoreductase

Title:

Crystal structure of thioredoxin e101g mutant

Structure:

Thioredoxin. Chain: a, b. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: trxa, bn17_37301, ecs4714. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.31Å R-factor: 0.176 R-free: 0.209

Authors:

M.E.Noguera,D.S.Vazquez,E.I.Howard,A.Cousido-Siah,A.Mitschler, A.Podjarny,J.Santos

Key ref:

M.E.Noguera et al. (2017). Structural variability of E. coli thioredoxin captured in the crystal structures of single-point mutants. Sci Rep, 7, 42343. PubMed id: 28181556

Date:

22-Jan-16 Release date: 22-Feb-17

Protein chains

P0AA25  (THIO_ECOLI) -  Thioredoxin 1 from Escherichia coli (strain K12)

Seq: 109 a.a.

Struc: 108 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Sci Rep 7:42343 (2017)

PubMed id: 28181556

Structural variability of E. coli thioredoxin captured in the crystal structures of single-point mutants.

M.E.Noguera, D.S.Vazquez, G.Ferrer-Sueta, W.A.Agudelo, E.Howard, R.M.Rasia, B.Manta, A.Cousido-Siah, A.Mitschler, A.Podjarny, J.Santos.

ABSTRACT

Thioredoxin is a ubiquitous small protein that catalyzes redox reactions of protein thiols. Additionally, thioredoxin from E. coli (EcTRX) is a widely-used model for structure-function studies. In a previous paper, we characterized several single-point mutants of the C-terminal helix (CTH) that alter global stability of EcTRX. However, spectroscopic signatures and enzymatic activity for some of these mutants were found essentially unaffected. A comprehensive structural characterization at the atomic level of these near-invariant mutants can provide detailed information about structural variability of EcTRX. We address this point through the determination of the crystal structures of four point-mutants, whose mutations occurs within or near the CTH, namely L94A, E101G, N106A and L107A. These structures are mostly unaffected compared with the wild-type variant. Notably, the E101G mutant presents a large region with two alternative traces for the backbone of the same chain. It represents a significant shift in backbone positions. Enzymatic activity measurements and conformational dynamics studies monitored by NMR and molecular dynamic simulations show that E101G mutation results in a small effect in the structural features of the protein. We hypothesize that these alternative conformations represent samples of the native-state ensemble of EcTRX, specifically the magnitude and location of conformational heterogeneity.