Protein Secretion in Streptomyces
Tracy Palmer and Matthew I. Hutchings
from: Streptomyces: Molecular Biology and Biotechnology (Edited by: Paul Dyson). Caister Academic Press, U.K. (2011)
The saprophytic lifestyle of Streptomyces requires them to secrete prolific numbers of proteins. For example, inspection of the genome sequence of Streptomyces coelicolor indicates it encodes some 819 proteins with predicted signal peptides. This represents more than 10% of the protein coding genes and is most likely an underestimate. Many secreted proteins are required for nutrient capture, and there is an abundance of secreted hydrolases for the breakdown of complex carbohydrates (including cellulose and chitin), peptides and phospho-compounds. In addition to proteins that are secreted into the milieu, many proteins are covalently anchored to the cell surface by means of either a lipid anchor to the membrane or by covalent attachment to the cell wall through the sortase system. Here we summarise what is known about the different protein secretion systems utilised by Streptomyces, and the mechanisms by which proteins are anchored to the extracellular surface read more ...