KpsC is a beta-3-deoxy-D-manno-oct-2-ulosonic acid (Kdo)-transferase. It is part of the ATP-binding cassette transporter dependent capsular polysaccharides (CPSs) synthesis pathway, one of two CPS synthesis pathways present in Escherichia coli. The poly-Kdo linker is thought to be the common feature of CPSs synthesized via this pathway. CPSs are high-molecular-mass cell-surface polysaccharides that are important virulence factors for many pathogenic bacteria. KpsC contains a domain duplication.