The 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase HSD-X1 of Pseudomonas Citronellolis SJTE-3 Catalyzes the Conversion of 17β-estradiol to Estrone

Protein Pept Lett. 2022;29(3):199-207. doi: 10.2174/0929866529666220113140721.

Abstract

Background: Pseudomonas citronellolis SJTE-3 can efficiently degrade 17β-estradiol (E2) and other estrogenic chemicals. However, the enzyme responsible for E2 metabolism within strain SJTE-3 has remained unidentified.

Objective: Here, a novel 3-oxoacyl-(acyl-carrier protein) (ACP) reductase, HSD-X1 (WP_ 009617962.1), was identified in SJTE-3 and its enzymatic characteristics for the transformation of E2 were investigated.

Methods: Multiple sequence alignment and homology modelling were used to predict the protein structure of HSD-X1. The concentrations of different steroids in the culture of recombinant strains expressing HSD-X1 were determined by high performance liquid chromatography. Additionally, the transcription of hsd-x1 gene was investigated using reverse transcription and quantitative PCR analysis. Heterologous expression and affinity purification were used to obtain recombinant HSD- X1.

Results: The transcription of hsd-x1 gene in P. citronellolis SJTE-3 was induced by E2. Multiple sequence alignment (MSA) indicated that HSD-X1 contained the two consensus regions and conserved residues of short-chain dehydrogenase/reductases (SDRs) and 17β-hydroxysteroid dehydrogenases (17β-HSDs). Over-expression of hsd-x1 gene allowed the recombinant strain to degrade E2. Recombinant HSD-X1 was purified with a yield of 22.15 mg/L and used NAD+ as its cofactor to catalyze the oxidization of E2 into estrone (E1) while exhibiting a Km value of 0.025 ± 0.044 mM and a Vmax value of 4.92 ± 0.31 mM/min/mg. HSD-X1 could tolerate a wide range of temperature and pH, while the presence of divalent ions exerted little influence on its activity. Further, the transformation efficiency of E2 into E1 was over 98.03% across 15 min.

Conclusion: Protein HSD-X1 efficiently catalyzed the oxidization of E2 and participated in estrogen degradation by P. citronellolis SJTE-3.

Keywords: 17β-estradiol; 17β-hydroxysteroid dehydrogenase; 3-oxoacyl-ACP reductase; E2 metabolism; MSA; Pseudomonas citronellolis SJTE-3; estrone.

MeSH terms

  • 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase / metabolism
  • Acyl Carrier Protein*
  • Estradiol / metabolism
  • Estrone* / metabolism
  • Oxidoreductases / genetics
  • Oxidoreductases / metabolism
  • Pseudomonas

Substances

  • Acyl Carrier Protein
  • Estrone
  • Estradiol
  • Oxidoreductases
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Reductase

Supplementary concepts

  • Pseudomonas citronellolis