fusABC is required for growth on inulin. (A) Schematic of putative fructooligosaccharide ABC transporters in S. pneumoniae strains TIGR4 and D39. Open reading frames predicted within the TIGR4 and D39 sequences are represented by block arrows. Arrows above the schematic indicate predicted transcriptional start sites, and the predicted terminators are denoted by a stem-loop (2). A gene predicted to encode a LacI family repressor is present in both loci but shows high diversity (fusR and sfuR), while the sucrose hydrolase gene fusH is conserved across pneumococcal strains. Also conserved is the first gene of each genomic locus, predicted to encode a transcriptional activator. Pneumococcal strains were grown for 60 h on CDM supplemented with 12 mM GF3 (B), 5 mg ml−1 inulin (C), 12 mM glucose (not shown), or no carbohydrate (not shown) as the sole carbon source. Symbols on the top left of the graphs indicate the structure of the carbohydrate source: ○, fructose; ▲, glucose. Growth was measured by determination of the optical density at 600 nm. Each experiment was performed at least three independent times in triplicate, and the average data from one experiment are shown.