71 Proteomics of haematococcus pluvialis: new opportunities for study of genomics of a non‐sequenced species

Abstract

The green alga, Haematococcus pluvialis, has become a model organism for commercial production of the high‐value carotenoid astaxanthin. H. Pluvialis has also drawn significant scientific attention because fundamental biological questions relating to the massive cellular accumulation of astaxanthin have to be addressed in order to improve the yield and quality of the algal biomass. However, research has been impeded by the lack of molecular background information on this non‐sequenced species. A combination of classical biochemistry with a state‐of‐the‐art proteomic approach was used to address these questions. This was possible by taking advantage of information already available for homologous genes/gene‐products in organisms whose genomes have been sequenced. The approach involved isolation of subsets of the proteome from subcellular compartments/organelles of an organism by one‐ or two‐dimensional electrophoresis (1‐DE or 2‐DE) and their identification by N‐terminal sequencing and peptide mass fingerprinting (PMF), involving matrix‐assisted laser desorption/ionization and time‐of‐flight (MALDI‐TOF) mass spectrometry coupled with bioinformatics. Based upon the information obtained from the combined methods, expression and physiological functions of specific genes/encoded proteins may be deduced. Examples include profiling of cell wall proteins, biogenesis and protein composition of lipid bodies, and expression patterns of soluble proteins under stress conditions. Advantages and limitations of the method for non‐sequenced organisms and for cross‐species protein identification will also be discussed.