Involved in the hydrocarbon hydroxylating system, which transfers electrons from NADH to rubredoxin reductase and then through rubredoxin to alkane 1 monooxygenase. Binds 2 Fe(3+) ions per subunit. Hydrocarbon metabolism; alkane degradation. Induced by AlkS and n-alkanes. Unlike other rubredoxins, this rubredoxin is unique in that it contains two binding sites for iron. It is most probably the product of a gene duplication event. The 2Fe form of the rubredoxin is a physiological form but it is less stable than the readily isolated 1Fe form. Both domains can form productive electron transfer complexes with rubredoxin reductase and accept electrons from the enzyme bound FAD. Belongs to the rubredoxin family.