Involved in the utilization of cholesterol as the sole carbon and energy source by degrading the side chain during infection. Primarily catalyzes the sequential oxidation of the terminal methyl of cholest-4-en-3-one into (25S)-26-hydroxycholest-4-en-3-one (alcohol), (25S)-26-oxocholest-4-en-3-one (aldehyde), to finally yield the carboxylic acid (25S)-3-oxocholest-4-en-26-oate. Also able to sequentially oxidize cholesterol itself, not only cholest-4-en-3-one. cholest-4-en-3-one + 5 H(+) + 3 O2 + 6 reduced [2Fe-2S]-[ferredoxin] = (25S)-3-oxocholest-4-en-26-oate + 4 H2O + 6 oxidized [2Fe-2S]-[ferredoxin] Steroid metabolism; cholesterol degradation. By cholesterol. Cells lacking this genes can transform cholesterol but is unable to metabolize it sufficiently to support growth. 4-cholesten-3-one is accumulated when incubated in the presence of cholesterol. Belongs to the cytochrome P450 family.