title: Proteomic analysis of the carotenogenic yeast Xanthophyllomyces dendrorhous.
abstract: BACKGROUND
  The yeast Xanthophyllomyces dendrorhous is used for the microbiological production of the antioxidant carotenoid astaxanthin. In this study, we established an optimal protocol for protein extraction and performed the first proteomic analysis of the strain ATCC 24230. Protein profiles before and during the induction of carotenogenesis were determined by two-dimensional polyacrylamide gel electrophoresis and proteins were identified by mass spectrometry.
  
  
  RESULTS
  Among the approximately 600 observed protein spots, 131 non-redundant proteins were identified. Proteomic analyses allowed us to identify 50 differentially expressed proteins that fall into several classes with distinct expression patterns. These analyses demonstrated that enzymes related to acetyl-CoA synthesis were more abundant prior to carotenogenesis. Later, redox- and stress-related proteins were up-regulated during the induction of carotenogenesis. For the carotenoid biosynthetic enzymes mevalonate kinase and phytoene/squalene synthase, we observed higher abundance during induction and/or accumulation of carotenoids. In addition, classical antioxidant enzymes, such as catalase, glutathione peroxidase and the cytosolic superoxide dismutases, were not identified.
  
  
  CONCLUSIONS
  Our results provide an overview of potentially important carotenogenesis-related proteins, among which are proteins involved in carbohydrate and lipid biosynthetic pathways as well as several redox- and stress-related proteins. In addition, these results might indicate that X. dendrorhous accumulates astaxanthin under aerobic conditions to scavenge the reactive oxygen species (ROS) generated during metabolism.
authors.affiliation: Departamento de Ciencias Ecológicas, Centro de Biotecnologia, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
authors.forename: Pilar
authors.initials: P
authors.lastname: Martinez-Moya
authors.forename: Steven Alexander
authors.initials: SA
authors.lastname: Watt
authors.forename: Karsten
authors.initials: K
authors.lastname: Niehaus
authors.forename: Jennifer
authors.initials: J
authors.lastname: Alcaíno
authors.forename: Marcelo
authors.initials: M
authors.lastname: Baeza
authors.forename: Víctor
authors.initials: V
authors.lastname: Cifuentes
mesh_terms: D001487:Basidiomycota / Q000737:chemistry*; D015180:Electrophoresis, Gel, Two-Dimensional; D005656:Fungal Proteins / Q000032:analysis*; D013058:Mass Spectrometry; D020543:Proteome / Q000032:analysis*; D024341:Xanthophylls / Q000096:biosynthesis
chemical_list: D005656:Fungal Proteins; D020543:Proteome; D024341:Xanthophylls; C005948:astaxanthine