title: Cyclic AMP (cAMP) Receptor Protein-cAMP Complex Regulates Heparosan Production in Escherichia coli Strain Nissle 1917.
abstract: Heparosan serves as the starting carbon backbone for the chemoenzymatic synthesis of heparin, a widely used clinical anticoagulant drug. The availability of heparosan is a significant concern for the cost-effective synthesis of bioengineered heparin. The carbon source is known as the pivotal factor affecting heparosan production. However, the mechanism by which carbon sources control the biosynthesis of heparosan is unclear. In this study, we found that the biosynthesis of heparosan was influenced by different carbon sources. Glucose inhibits the biosynthesis of heparosan, while the addition of either fructose or mannose increases the yield of heparosan. Further study demonstrated that the cyclic AMP (cAMP)-cAMP receptor protein (CRP) complex binds to the upstream region of the region 3 promoter and stimulates the transcription of the gene cluster for heparosan biosynthesis. Site-directed mutagenesis of the CRP binding site abolished its capability of binding CRP and eliminated the stimulative effect on transcription. (1)H nuclear magnetic resonance (NMR) analysis was further performed to determine the Escherichia coli strain Nissle 1917 (EcN) heparosan structure and quantify extracellular heparosan production. Our results add to the understanding of the regulation of heparosan biosynthesis and may contribute to the study of other exopolysaccharide-producing strains.
authors: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui, China Wanjiang Institute of Poultry Technology, Hefei University of Technology, Xuancheng Campus, Xuancheng, Anhui, China.
authors: Huihui
authors: H
authors: Yan
authors: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui, China Wanjiang Institute of Poultry Technology, Hefei University of Technology, Xuancheng Campus, Xuancheng, Anhui, China.
authors: Feifei
authors: F
authors: Bao
authors: School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
authors: Liping
authors: L
authors: Zhao
authors: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui, China Wanjiang Institute of Poultry Technology, Hefei University of Technology, Xuancheng Campus, Xuancheng, Anhui, China.
authors: Yanying
authors: Y
authors: Yu
authors: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui, China Wanjiang Institute of Poultry Technology, Hefei University of Technology, Xuancheng Campus, Xuancheng, Anhui, China.
authors: Jiaqin
authors: J
authors: Tang
authors: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui, China Wanjiang Institute of Poultry Technology, Hefei University of Technology, Xuancheng Campus, Xuancheng, Anhui, China zhoux@hfut.edu.cn.
authors: Xianxuan
authors: X
authors: Zhou
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002373:Cyclic AMP Receptor Protein / Q000235:genetics* / Q000378:metabolism; D004187:Disaccharides / Q000096:biosynthesis*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005632:Fructose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D008358:Mannose / Q000378:metabolism
chemical_list: D002373:Cyclic AMP Receptor Protein; D004187:Disaccharides; D029968:Escherichia coli Proteins; C481662:crp protein, E coli; C560363:heparosan; D005632:Fructose; D002244:Carbon; D005947:Glucose; D008358:Mannose