|PROSITE documentation PDOC00176|
Ferredoxins  are a group of iron-sulfur proteins which mediate electron transfer in a wide variety of metabolic reactions. Ferredoxins can be divided into several subgroups depending upon the physiological nature of the iron-sulfur cluster(s). One of these subgroups are the 4Fe-4S ferredoxins, which are found in bacteria and which are thus often referred as 'bacterial-type' ferredoxins. The structure of these proteins  consists of the duplication of a domain of twenty six amino acid residues; each of these domains contains four cysteine residues that bind to a 4Fe-4S center.
Several structures of the 4Fe-4S ferredoxin domain have been determined (see for example <PDB:1FDN>) . The clusters consist of two interleaved 4Fe- and 4S-tetrahedra forming a cubane-like structure, in such a way that the four iron occupy the eight corners of a distorted cube. Each 4Fe-4S is attached to the polypeptide chain by four covalent Fe-S bonds involving cysteine residues.
A number of proteins have been found  that include one or more 4Fe-4S binding domains similar to those of bacterial-type ferredoxins. These proteins are listed below:
The pattern of cysteine residues in the iron-sulfur region is sufficient to detect this class of 4Fe-4S binding proteins. The profile we developed covers the whole domain.Note:
In some bacterial ferredoxins, one of the two duplicated domains has lost one or more of the four conserved cysteines. The consequence of such variations is that these domains have either lost their iron-sulfur binding property or bind to a 3Fe-4S center instead of a 4Fe-4S center.Note:
The last residue of this pattern in most proteins belonging to this group, is a Pro; the only exceptions are the Rhizobium ferredoxin-like proteins which have Gly, and two Desulfovibrio ferredoxins which have Glu. It must also be noted that the three non 4Fe-4S-binding proteins which are picked-up by the pattern have Gly in this position of the pattern.Last update:
April 2008 / Text revised; profile added.
PROSITE methods (with tools and information) covered by this documentation:
|Title||The evolution of ferredoxins.|
|Source||Trends Ecol. Evol. 3:222-226(1988).|
|2||Authors||Otaka E. Ooi T.|
|Title||Examination of protein sequence homologies: IV. Twenty-seven bacterial ferredoxins.|
|Source||J. Mol. Evol. 26:257-267(1987).|
|3||Authors||Duee E.D. Fanchon E. Vicat J. Sieker L.C. Meyer J. Moulis J.M.|
|Title||Refined crystal structure of the 2[4Fe-4S] ferredoxin from Clostridium acidurici at 1.84 A resolution.|
|Source||J. Mol. Biol. 243:683-695(1994).|
|Title||Recent developments in the field of iron-sulfur proteins.|
|Source||FASEB J. 4:2483-2491(1990).|
|5||Authors||Huang C.J. Barrett E.L.|
|Title||Sequence analysis and expression of the Salmonella typhimurium asr operon encoding production of hydrogen sulfide from sulfite.|
|Source||J. Bacteriol. 173:1544-1553(1991).|
|Title||The photosystem I reaction centre.|
|Source||Trends Biochem. Sci. 13:460-461(1988).|