Profiling and Structural Characterization of High Neu5Gc or Sulfate-Containing O-glycans from Hyla Rabbit Intestinal Mucin

Intestinal mucins constitute the major component of the mucus covering the epithelium of the gastrointestinal tract, thereby forming a barrier against microbial colonization. Rabbits are bred in large numbers worldwide, with little known about intestinal O-glycosylation despite this insight being crucial to the understanding of host-pathogen interactions. In the present study, a major mucin-type glycopeptide (RIF6) of hyla rabbit intestine was isolated and the O-glycans were extensively characterized based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) combined with bioinformatics approaches. Thirty-three O-glycans were identified, and most of them were sulfated or sialylated glycans. It was worth noting that Neu5Gc-containing structures within sialylated O-glycans accounted for 91%, which were extremely different from that of other species including humans, mice, chickens, etc. Sulfated glycans accounted for 58%, unique disufated and sulfated-sialylated glycans were also detected in rabbit intestinal mucin. These structural characterization reflected species diversity and may provide deeper insights into explaining the adaptability of hyla rabbit to the environment.