Identification and characterization of a 20β-HSDH from the anaerobic gut bacteriumButyricicoccus desmolansATCC 43058.
Members of the gastrointestinal microbiota are known to convert glucocorticoids to androstanes, which are subsequently converted to potent androgens by other members of the gut microbiota or host tissues.Butyricicoccus desmolansandClostridium cadaverishave previously been reported for steroid-17,20-desmolase and 20β-hydroxysteroid dehydrogenase (HSDH) activities that are responsible for androstane formation from cortisol; however, the genes encoding these enzymes have yet to be reported. In this work, we identified and located a gene encoding 20β-HSDH in bothB. desmolansandC. cadaverisThe 20β-HSDH ofB. desmolanswas heterologously overexpressed and purified fromEscherichia coliThe enzyme was determined to be a homotetramer with subunit molecular mass of 33.8 ± 3.7 kDa. The r20β-HSDH displayed pH optimum in the reductive direction at pH 9.0 and in the oxidative direction at pH 7.0-7.5 with (20β-dihydro)cortisol and NAD(H) as substrates. Cortisol is the preferred substrate withKm, 0.80 ± 0.06 μM;Vmax, 30.36 ± 1.97 μmol·min-1;Kcat, 607 ± 39 μmol·μM-1·min-1;Kcat/Km, 760 ± 7.67. Phylogenetic analysis of the 20β-HSDH fromB. desmolanssuggested that the 20β-HSDH is found in severalBifidobacterium spp, one of which was shown to express 20β-HSDH activity. Notably, we also identified a novel steroid-17,20-desmolase-elaborating bacterium,Propionimicrobium lymphophilum, a normal inhabitant of the urinary tract.
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Saravanan
S
Devendran
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Celia
C
Méndez-García
Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 jmridlon@illinois.edu.|Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801.|Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Jason M
JM
Ridlon
D000693:Anaerobiosis; D000073561:Clostridiaceae / Q000201:enzymology* / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D015964:Gene Expression Regulation, Bacterial; D006913:Hydroxysteroid Dehydrogenases / Q000235:genetics* / Q000378:metabolism*; D007422:Intestines / Q000382:microbiology*; D009876:Operon / Q000235:genetics; D010802:Phylogeny; D013256:Steroids / Q000378:metabolism
D013256:Steroids; D006913:Hydroxysteroid Dehydrogenases
20β-hydroxysteroid dehydrogenase; American Type Culture Collection; glucocorticoids; gut microbiota