CBB(3)-TYPE CYTOCHROME-OXIDASE IN THE OBLIGATELY CHEMOLITHOAUTOTROPHIC THIOBACILLUS SP W5

A highly active cytochrome c oxidase has been purified 75-fold from th e neutrophilic obligately autotrophic Thiobacillus sp. W5. UV/visible and electron paramagnetic resonance spectroscopy revealed that the cyt ochrome c oxidase contains low-spin hemes c and low- and high-spin hem es b. HPLC analysis confirmed the presence of heme b as the sole type of non-covalently bound heme. The combined data from atomic absorption spectroscopy and electron paramagnetic resonance indicate the absence of Curl and suggest the presence of a bimetallic heme-copper redox ce nter. These results show that Thiobacillus sp. W5 contains a cbb(3)-ty pe oxidase, which is a member of the heme-copper oxidase family. The c bb(3)-type oxidase was the only cytochrome oxidase expressed in aerobi cally and micro-aerobically grown Thiobacillus sp. W5 cultures.