3U99

The experimental X-ray structure of the new diheme cytochrome type c from Shewanella baltica OS155 sb-DHC

Summary for 3U99

• Entry DOI: 10.2210/pdb3u99/pdb
• Related: 1JNI 2CZS 2FW5 2FWT
• Descriptor: Diheme cytochrome c, HEME C (3 entities in total)
• Functional Keywords: cytochrome c fold, electron transfer protein, electron transport, diheme protein, bacterium shewanella baltica os155
• Biological source: Shewanella baltica
• Total number of polymer chains: 1
• Total formula weight: 17625.26

Authors

De March, M.,Di Rocco, G.,Geremia, S. (deposition date: 2011-10-18, release date: 2012-10-31, Last modification date: 2024-10-09)

Primary citation

De March, M.,Di Rocco, G.,Hickey, N.,Geremia, S.
High-resolution crystal structure of the recombinant diheme cytochrome c from Shewanella baltica (OS155).
J.Biomol.Struct.Dyn., 33:395-403, 2015

PubMed Abstract: Multiheme cytochromes c (cyts c) are c-type cyts characterized by non-standard structural and spectroscopic properties. The relative disposition of the heme cofactors in the core of these proteins is conserved and they can be classified from their geometry in two main groups. In one group the porphyrin planes are arranged in a perpendicular fashion, while in the other they are parallel. Orientation of the heme groups is a key factor that regulates the intramolecular electron transfer pathway. A 16.5 kDa diheme cyt c, isolated from the bacterium Shewanella baltica OS155 (Sb-DHC), was cloned and expressed in E. coli and its structure was investigated by X-ray crystallography. Using high-resolution data (1.14 Å) collected at ELETTRA (Trieste), the crystal structure, with an orthorhombic cell (a = 40.81, b = 42.97, c = 82.07 Å), was solved using the homologous diheme from Rhodobacter sphaeroides (Rs-DHC) as the initial model. The electron density map of the refined structure (Rfact of 13.8% and Rfree of 15.4%) shows a two domain structure connected by a central unstructured region (N72-G87). The Sb-DHC, like its homologue (Rs-DHC), folds into a new cyt c class: the N-terminal globular domain, with its three α-helices, belongs to class I of c-type cyts, while the C-terminal domain includes a rare π-helix. The metal centre of the c-type heme groups is axially coordinated by two His residues and it is covalently bound to the protein through two Cys bonds.

PubMed: 24559494
DOI: 10.1080/07391102.2014.880657

Experimental method

X-RAY DIFFRACTION (1.146 Å)