Substrate uptake and subcellular compartmentation of anoxic cholesterol catabolism in Sterolibacterium denitrificans

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Title:	Substrate uptake and subcellular compartmentation of anoxic cholesterol catabolism in Sterolibacterium denitrificans
Authors:	王柏翔;Lin, Ching-Wen;Wang, Po-Hsiang;Ismail, Wael;Tsai, Yu-Wen;El Nayal, Ashraf;Yang, Chia-Ying;Yang, Fu-Chun;Wang, Chia-Hsiang;Chiang, Yin-Ru
Contributors:	工學院環境工程研究所
Keywords:	Anaerobiosis;Bacterial Metabolism;Carbon Radioisotopes - chemistry;Cell Hypoxia;Cholestenones - chemistry;Cholestenones - metabolism;Cholesterol;Cholesterol - chemistry;Cholesterol - metabolism;Gram-negative Bacteria;Gram-Negative Bacteria - chemistry;Gram-Negative Bacteria - metabolism;Lipolysis;Metabolism - genetics;Metabolomics;Microbiology;Oxidation-Reduction;Periplasm - enzymology;Rhodocyclaceae - enzymology;Steroid Hormone;Sterols - chemistry;Sterols - metabolism;Subcellular Fractionation;Substrate Specificity
Date:	2015-01-09
Issue Date:	2026-04-23 15:09:44 (UTC+8)
Publisher:	American Society for Biochemistry and Molecular Biology Inc.;United States: Elsevier Inc
Abstract:	摘要： Cholesterol catabolism by actinobacteria has been extensively studied. In contrast, the uptake and catabolism of cholesterol by Gram-negative species are poorly understood. Here, we investigated microbial cholesterol catabolism at the subcellular level. 13C metabolomic analysis revealed that anaerobically grown Sterolibacterium denitrificans, a β-proteobacterium, adopts an oxygenase-independent pathway to degrade cholesterol. S. denitrificans cells did not produce biosurfactants upon growth on cholesterol and exhibited high cell surface hydrophobicity. Moreover, S. denitrificans did not produce extracellular catabolic enzymes to transform cholesterol. Accordingly, S. denitrificans accessed cholesterol by direction adhesion. Cholesterol is imported through the outer membrane via a putative FadL-like transport system, which is induced by neutral sterols. The outer membrane steroid transporter is able to selectively import various C27 sterols into the periplasm. S. denitrificans spheroplasts exhibited a significantly higher efficiency in cholest-4-en-3-one-26-oic acid uptake than in cholesterol uptake. We separated S. denitrificans proteins into four fractions, namely the outer membrane, periplasm, inner membrane, and cytoplasm, and we observed the individual catabolic reactions within them. Our data indicated that, in the periplasm, various periplasmic and peripheral membrane enzymes transform cholesterol into cholest-4-en-3-one-26-oic acid. The C27 acidic steroid is then transported into the cytoplasm, in which side-chain degradation and the subsequent sterane cleavage occur. This study sheds light into microbial cholesterol metabolism under anoxic conditions.Cholesterol is ubiquitous on earth. Little is known about anoxic cholesterol catabolism. We proposed a model for cholesterol uptake and subcellular compartmentation during cholesterol catabolism by a Gram-negative bacterium. The enzymes located in the periplasm are critical for cholesterol catabolism, especially during the steps of substrate activation. This study may have potential applications in the biotechnological production of steroid drugs. 其他題名： J Biol Chem 出版者： United States: Elsevier Inc 出版日期： 2015-01-09 出處： The Journal of biological chemistry, 2015-01, Vol.290 (2), p.1155-1169 資源來源： Alma/SFX Local Collection 版權： 2015 © 2015 ASBMB. Currently published by Elsevier Inc; originally published by American Society for Biochemistry and Molecular Biology. 版權： 2015 by The American Society for Biochemistry and Molecular Biology, Inc. 版權： 2015 by The American Society for Biochemistry and Molecular Biology, Inc. 2015 識別號： ISSN: 0021-9258 識別號： ISSN: 1083-351X 識別號： ISSN: 1067-8816 識別號： EISSN: 1083-351X 識別號： DOI: 10.1074/jbc.M114.603779 識別號： PMID: 25418128
Appears in Collections:	[Graduate Institute of Environmental Engineering ] journal & Dissertation

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