The SapB morphogen is a lantibiotic-like peptide derived from the product of the developmental gene ramS in Streptomyces coelicolor.
SapB is a morphogenetic peptide that is important for aerial mycelium formation by the filamentous bacterium Streptomyces coelicolor. Production of SapB commences during aerial mycelium formation and depends on most of the genes known to be required for the morphogenesis of aerial hyphae. Furthermore, the application of purified SapB to mutants blocked in morphogenesis restores their capacity to form aerial hyphae. Here, we present evidence that SapB is a lantibiotic-like peptide that is derived by posttranslational modification from the product of a gene (ramS) in the four-gene ram operon, which is under the control of the regulatory gene ramR. We show that the product of another gene in the operon (ramC) contains a region that is similar to enzymes involved in the biosynthesis of lantibiotics, suggesting that it might be involved in the posttranslational processing of RamS. We conclude that SapB is derived from RamS through proteolytic cleavage and the introduction of four dehydroalanine residues and two lanthionine bridges. We provide an example of a morphogenetic role for an antibiotic-like molecule.
Kodani
Shinya
S
Department of Biology, Hofstra University, Hempstead, NY 11549, USA.
Hudson
Michael E
ME
Durrant
Marcus C
MC
Buttner
Mark J
MJ
Nodwell
Justin R
JR
Willey
Joanne M
JM
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018507:Gene Expression Regulation, Developmental; D057927:Hydrophobic and Hydrophilic Interactions; D008025:Ligases / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D013302:Streptomyces / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; C055447:Streptomyces spore-associated proteins; D008025:Ligases