Structure at 1.0 A resolution of a high-potential iron-sulfur protein involved in the aerobic respiratory chain of Rhodothermus marinus.
The aerobic respiratory chain of the thermohalophilic bacterium Rhodothermus marinus, a nonphotosynthetic organism from the Bacteroidetes/Chlorobi group, contains a high-potential iron-sulfur protein (HiPIP) that transfers electrons from a bc 1 analog complex to a caa 3 oxygen reductase. Here, we describe the crystal structure of the reduced form of R. marinus HiPIP, solved by the single-wavelength anomalous diffraction method, based on the anomalous scattering of the iron atoms from the [4Fe-4S]3+/2+ cluster and refined to 1.0 A resolution. This is the first structure of a HiPIP isolated from a nonphotosynthetic bacterium involved in an aerobic respiratory chain. The structure shows a similar environment around the cluster as the other HiPIPs from phototrophic bacteria, but reveals several features distinct from those of the other HiPIPs of phototrophic bacteria, such as a different fold of the N-terminal region of the polypeptide due to a disulfide bridge and a ten-residue-long insertion.
Stelter
Meike
M
Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República (EAN), 2780-157 Oeiras, Portugal.
Melo
Ana M P
AM
Hreggvidsson
Sigridur
S
Saraiva
Lígia M
LM
Teixeira
Miguel
M
Archer
Margarida
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045245:Rhodothermus / Q000737:chemistry*; D016415:Sequence Alignment
D001426:Bacterial Proteins; D007506:Iron-Sulfur Proteins; D045322:Photosynthetic Reaction Center Complex Proteins; C007943:high potential iron-sulfur protein