PDBsum entry 3dr0

Electron transport

PDB id: 3dr0

Contents

Protein chains

93 a.a. *

Ligands

HEM ×3

SO4 ×2

Waters ×523

* Residue conservation analysis

PDB id:

3dr0

Name:

Electron transport

Title:

Structure of reduced cytochrome c6 from synechococcus sp. Pcc 7002

Structure:

Cytochrome c6. Chain: a, b, c. Synonym: soluble cytochrome f, cytochrome c553, cytochromE C-553. Engineered: yes

Source:

Synechococcus sp. Pcc 7002. Agmenellum quadruplicatum. Organism_taxid: 32049. Gene: petj. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

1.23Å R-factor: 0.108 R-free: 0.138

Authors:

W.Bialek,S.Krzywda,M.Jaskolski,A.Szczepaniak

Key ref:

W.Bialek et al. (2009). Atomic-resolution structure of reduced cyanobacterial cytochrome c6 with an unusual sequence insertion. Febs J, 276, 4426-4436. PubMed id: 19678839

Date:

10-Jul-08 Release date: 14-Jul-09

Protein chains

O30881  (CYC6_SYNP2) -  Cytochrome c6 from Picosynechococcus sp. (strain ATCC 27264 / PCC 7002 / PR-6)

Seq: 117 a.a.

Struc: 93 a.a.

Febs J 276:4426-4436 (2009)

PubMed id: 19678839

Atomic-resolution structure of reduced cyanobacterial cytochrome c6 with an unusual sequence insertion.

W.Bialek, S.Krzywda, M.Jaskolski, A.Szczepaniak.

ABSTRACT

The structure of the reduced form of cytochrome c(6) from the mesophilic cyanobacterium Synechococcus sp. PCC 7002 has been determined at 1.2 A and refined to an R-factor of 0.107. This protein is unique among all known cytochromes c(6), owing to the presence of an unusual seven-residue insertion, KDGSKSL(44-50), which differs from the insertion found in the recently discovered plant cytochromes c(6A). Furthermore, the present protein is unusual because of its very high content (36%) of the smallest residues (glycine and alanine). The structure reveals that the overall fold of the protein is similar to that of other class I c-type cytochromes, despite the presence of the specific insertion. The insertion is located within the most variable region of the cytochrome c(6) sequence, i.e. between helices II and III. The first six residues [KDGSKS(44-49)] form a loop, whereas the last residue, Leu50, extends the N-terminal beginning of helix III. Several specific noncovalent interactions are found inside the insertion, as well as between the insertion and the rest of the protein. The crystal structure contains three copies of the cytochrome c(6) molecule per asymmetric unit, and is characterized by an unusually high packing density, with solvent occupying barely 17.58% of the crystal volume.