DNA-SEQUENCE OF THE CUT-A, CUT-B AND CUT-C GENES, ENCODING THE MOLYBDENUM-CONTAINING HYDROXYLASE CARBON-MONOXIDE DEHYDROGENASE, FROM PSEUDOMONAS THERMOCARBOXYDOVORANS STRAIN C2

Pseudomonas thermocarboxydovorans strain C2 is capable of using carbon monoxide as the sole source of carbon and energy. The key enzyme for CO utilisation is the molybdenum containing iron-flavoprotein carbon m onoxide dehydrogenase (CODH). This paper reports the DNA sequencing of a 4.7 kb region of the C2 genome which appears to encode the CODH enz yme. The genes for the three subunits of CODH, which we have named cut A, B and C, have been identified and they appear to form an operon. T he predicted protein sequences of the three subunits have homology to the structurally related protein, xanthine dehydrogenase, from Drosoph ila melanogaster. By comparison with xanthine dehydogenase it can be p redicted that the molybdenum cofactor binds to the large subunit of CO DH, the small subunit of CODH contains the iron-sulphur centers and th e medium subunit binds FAD/NAD +.