PDBsum entry 1cc3

Electron transport

PDB id: 1cc3

Contents

Protein chains

130 a.a. *

Metals

_CU ×4

Waters ×506

* Residue conservation analysis

PDB id:

1cc3

Name:

Electron transport

Title:

Purple cua center

Structure:

Protein (cua azurin). Chain: a, b. Engineered: yes. Other_details: azurine with the following mutations: the loop 113-118 tfpghs was replaced with 113-120 selcginh

Source:

Pseudomonas aeruginosa. Organism_taxid: 287. Expressed in: escherichia coli. Expression_system_taxid: 562. Other_details: loop directed mutagenesis

Resolution:

1.65Å R-factor: 0.201 R-free: 0.263

Authors:

H.Robinson,M.C.Ang,Y.-G.Gao,M.T.Hay,Y.Lu,A.H.-J.Wang

Key ref:

H.Robinson et al. (1999). Structural basis of electron transfer modulation in the purple CuA center. Biochemistry, 38, 5677-5683. PubMed id: 10231517 DOI: 10.1021/bi9901634

Date:

03-Mar-99 Release date: 23-Dec-99

Protein chains

P00282  (AZUR_PSEAE) -  Azurin from Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)

Seq: 148 a.a.

Struc: 130 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

DOI no: 10.1021/bi9901634

Biochemistry 38:5677-5683 (1999)

PubMed id: 10231517

Structural basis of electron transfer modulation in the purple CuA center.

H.Robinson, M.C.Ang, Y.G.Gao, M.T.Hay, Y.Lu, A.H.Wang.

ABSTRACT

The X-ray structure of an engineered purple CuA center in azurin from Pseudomonas aeruginosa has been determined and refined at 1.65 A resolution. Two independent purple CuA azurin molecules are in the asymmetric unit of a new P21 crystal, and they have nearly identical conformations (rmsd of 0.27 A for backbone atoms). The purple CuA azurin was produced by the loop-engineering strategy, and the resulting overall structure is unperturbed. The insertion of a slightly larger Cu-binding loop into azurin causes the two structural domains of azurin to move away from each other. The high-resolution structure reveals the detailed environment of the delocalized mixed-valence [Cu(1.5).Cu(1.5)] binuclear purple CuA center, which serves as a useful reference model for other native proteins, and provides a firm basis for understanding results from spectroscopic and functional studies of this class of copper center in biology. The two independent Cu-Cu distances of 2.42 and 2.35 A (with respective concomitant adjustments of ligand-Cu distances) are consistent with that (2.39 A) obtained from X-ray absorption spectroscopy with the same molecule, and are among the shortest Cu-Cu bonds observed to date in proteins or inorganic complexes. A comparison of the purple CuA azurin structure with those of other CuA centers reveals an important relationship between the angular position of the two His imidazole rings with respect to the Cu2S2(Cys) core plane and the distance between the Cu and the axial ligand. This relationship strongly suggests that the fine structural variation of different CuA centers can be correlated with the angular positions of the two histidine rings because, from these positions, one can predict the relative axial ligand interactions, which are responsible for modulating the Cu-Cu distance and the electron transfer properties of the CuA centers.