Mitarbeitende
- Franziska Feller
- Laura Heisel
- Johannes Holert
- Karin Niermann
- Tim Weckerle
- Julia Wessel
Thematik
Steroids are ubiquitous organic compounds with diverse functions in eukaryotic organisms. In bacteria, steroids occur only as rare exceptions. However, many bacteria are able to transform and degrade steroid compounds. Bacterial transformation of steroids is an essential part of the biotechnological production of steroid hormones. In comparison to the degradation of other natural compounds the bacterial degradation of steroids has only scarcely been explored. We study bacterial steroid metabolism with different model organisms and the steroid compound cholate (a bile salt) as a model substrate.
The goal of our research is to use knowledge about bacterial steroid metabolism for engineering novel bacterial biocatalysts for biotechnological steroid production. Furthermore, we are interested in the degradation of synthetic steroids, which can act as endocrine disruptors.
The current view of bacterial steroid degradation is that various steroids are transformed into derivatives of androstadienediones (ADDs) as central intermediates. These transformations involve oxidative reactions at the A-ring and removal of the steroid side chain. ADDs are then converted into so-called seco-steroids with an aromatic A-ring and a broken B-ring.
Our major focus is on the removal of the steroid side chain. We have identified several genes in Pseudomonas sp. strain Chol1 that encode essential proteins for degrading the acyl side chain of cholate. The following figure summarizes the current picture of cholate degradation in Pseudomonas sp. Strain Chol1.
Cholate degradation in Pseudomonas sp. strain Chol1 as an example for bacterial degradation of steroids© IMMB Ausgewählte Publikationen
Yücel O, Drees S, Jagmann N, Patschkowski T, Philipp B (2016) An unexplored pathway for degradation of cholate requires a 7α-hydroxysteroid dehydratase and contributes to a broad metabolic repertoire for the utilization of bile salts in Novosphingobium sp. strain Chol11.
Environmental Microbiology, doi: 10.1111/1462-2920.13534Holert J, Yücel O, Jagmann N, Prestel A, Möller H, Philipp B (2015) Identification of bypass reactions leading to the formation of one central steroid degradation intermediate in metabolism of different bile salts in Pseudomonas sp. strain Chol1.
Enivronmental Microbiology 2015 Dec 22. doi: 10.1111/1462-2920.13192Holert J, Yücel O, Suvekbala V, Kulic, Z, Möller HM, Philipp B (2014) Evidence of distinct pathways for bacterial degradation of the steroid compound cholate suggests the potential for metabolic interactions by interspecies cross-feeding.
Environmental Microbiology 16(5): 1424-1440Holert J, Jagmann N, Philipp B (2013) The essential function of genes for a hydratase and an aldehyde dehydrogenase for growth of Pseudomonas sp. strain Chol1 with the steroid compound cholate indicates an aldolytic reaction step for deacetylation of the side chain.
Journal of Bacteriology 195: 3371-3380Holert J, Alam I, Larsen M, Antunes A, Bajic VB, Stingl U, Philipp B (2013) Genome sequence of Pseudomonas sp. strain Chol1, a model organism for the degradation of bile salts and other steroid compounds.
Genome Announcement 1(1): e00014-12. doi:10.1128/genomeA.00014-12Holert J, Kulic Z, Yücel O, Suvekbala V, Suter MJ-F, Möller H, Philipp B (2013) Degradation of the acyl side chain of the steroid compound cholate in Pseudomonas sp. strain Chol1 proceeds via an aldehyde intermediate.
Journal of Bacteriology 195: 585-595Philipp B (2011) Bacterial degradation of bile salts.
Applied Microbiology and Biotechnology 89: 903-915
Birkenmaier A, Holert J, Erdbrink H, Möller H, Friemel A, Schönenberger R, Suter MJ-F, Klebensberger J, Philipp B (2007) Biochemical and genetic investigation on initial reactions in aerobic degradation of the bile acid cholate in Pseudomonas sp. strain Chol1.
Journal of Bacteriology 189: 7165-7173