Biomaterial Database

New stereochemical analogies between iron-sulfur electron transport proteins. 1977

C W Carter

Active sites of Chromatium high potential iron protein (HiPIP) and Pseudomonas Aerogenes ferredoxin can be brought into equivalent orientations by assuming that their Fe4S4Sgamma4 clusters have the effective symmetry of the non-axial molecular point group Cs. Previously undetected analogies between the two proteins emerge as a result of selecting a common orientation in this mammer. Polypeptide segments connecting Cys 46 to Cys 63 in HiPIP and Cys 18 to Cys 35 in ferredoxin are analogous in the sense that they are the same length, they connect equivalent cysteinyl sulfur atoms, and they have similar, twisted antiparalled beta conformations. Tyrosine residues 19 (HiPIP) and 2 (ferredoxin) are analogous in the sense that they interact closely with equivalent inorganic sulfur atoms. To a good approximation, interactions with the polypeptide backbone and with tyrosine side chains in the two proteins place their Fe4S4Sgamma4 moieties into diastereomeric environments, which would be expected to induce different physical and chemical behavior. Circular dichroism spectra of native and super reducible HiPIP (Cammack, R. (1973) Biochem. Biophys. Res. Commun. 54, 548-554) suggest that this relationship can help to explain the contrasting oxidoreduction properties of the two proteins.

UI	MeSH Term	Description	Entries
D007506	Iron-Sulfur Proteins	A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.	Iron-Sulfur Protein,Iron Sulfur Proteins,Iron Sulfur Protein,Protein, Iron-Sulfur,Proteins, Iron Sulfur,Proteins, Iron-Sulfur,Sulfur Proteins, Iron
D008667	Metalloproteins	Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)	Metalloprotein
D008958	Models, Molecular	Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.	Molecular Models,Model, Molecular,Molecular Model
D008968	Molecular Conformation	The characteristic three-dimensional shape of a molecule.	Molecular Configuration,3D Molecular Structure,Configuration, Molecular,Molecular Structure, Three Dimensional,Three Dimensional Molecular Structure,3D Molecular Structures,Configurations, Molecular,Conformation, Molecular,Conformations, Molecular,Molecular Configurations,Molecular Conformations,Molecular Structure, 3D,Molecular Structures, 3D,Structure, 3D Molecular,Structures, 3D Molecular
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D011549	Pseudomonas	A genus of gram-negative, aerobic, rod-shaped bacteria widely distributed in nature. Some species are pathogenic for humans, animals, and plants.	Chryseomonas,Pseudomona,Flavimonas
D002844	Chromatium	A genus of gram-negative, ovoid to rod-shaped bacteria that is phototrophic. All species use ammonia as a nitrogen source. Some strains are found only in sulfide-containing freshwater habitats exposed to light while others may occur in marine, estuarine, and freshwater environments.
D002942	Circular Dichroism	A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Circular Dichroism, Vibrational,Dichroism, Circular,Vibrational Circular Dichroism
D005288	Ferredoxins	Iron-containing proteins that transfer electrons, usually at a low potential, to flavoproteins; the iron is not present as in heme. (McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Ferredoxin,Ferredoxin I,Ferredoxin II,Ferredoxin III
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining