Substrate Inhibition of 5β-Δ⁴-3-Ketosteroid Dehydrogenase in Sphingobium sp. Strain Chol11 Acts as Circuit Breaker During Growth With Toxic Bile Salts.

ABSTRACT: In contrast to many steroid hormones and cholesterol, mammalian bile salts are 5β-steroids, which leads to a bent structure of the steroid core. Bile salts are surface-active steroids excreted into the environment in large amounts, where they are subject to bacterial degradation. Bacterial steroid degradation is initiated by the oxidation of the A-ring leading to canonical Δ⁴-3-keto steroids with a double bond in the A-ring. For 5β-bile salts, this Δ⁴-double bond is introduced into 3-keto-bile salts by a 5β-Δ⁴-ketosteroid dehydrogenase (5β-Δ⁴-KSTD). With the Nov2c019 protein from bile-salt degrading Sphingobium sp. strain Chol11, a novel 5β-Δ⁴-KSTD for bile-salt degradation belonging to the Old Yellow Enzyme family was identifie

SUBMITTER: Feller FM 

PROVIDER: S-EPMC8044976 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature