ERGOTHIONEINE DEGRADATION AND PROPERTIES OF ERGOTHIONASE FROM AGROBACTERIUM RADIOBACTER

Open Access
Author:
Manamtharayil Jose, Jiku
Area of Honors:
Biochemistry and Molecular Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Allen T Phillips, Thesis Supervisor
  • Chen Pei David Tu, Honors Advisor
  • Wendy Hanna Rose, Faculty Reader
Keywords:
  • Ergothioneine
  • Ergothionase
  • Agrobacterium
  • enzyme properties
  • Nitrogen utilization
  • Km
  • Vmax
  • King Oyster mushroom
  • Alumina column
  • Adsorption chromatography
  • Antioxidant
  • Oxidative Stress
  • Thiolurocanic acid
  • Trimethylamine
  • Ergothioneine biodegradation.
Abstract:
Ergothioneine is a naturally occurring sulfur containing amino acid that is obtained through the diet and is assimilated by several tissues in millimolar concentrations, where it functions as a natural antioxidant and part of the thiol defense system against oxidative stress. With the emerging role of oxidative stress in the etiology of various cardiovascular and neurological diseases, the study of ergothioneine biodegradation pathway is very crucial. In this study, we investigated the ability of a bacterial strain, Agrobacterium radiobacter, to degrade ergothioneine and use it as a sole nitrogen source for growth. The characteristics of the enzyme ergothionase, which is responsible for the breakdown of ergothioneine, were examined. We made an effort to extract ergothioneine from the ergothioneine synthesizing King Oyster mushrooms. The protective role of ergothioneine against oxidative stress in Agrobacterium was also studied. Our data suggest that the Agrobacterium radiobacter is capable of utilizing ergothioneine as a sole nitrogen source, where ergothionase degrades ergothioneine into its first intermediate product thiolurocanate and the byproduct trimethylamine. We found that A. radiobacter uses only two of the three nitrogen atoms present in ergothioneine for its growth. Ergothioneine also had a protective role against oxidative stress induced by H2O2 in Agrobacterium. Ergothioneine was successfully extracted from King Oyster mushroom powder through a three step purification procedure.