Immunogen sequence: SCKPFKWYLE NVYPELRVPD HQDIAFGALQ QGTNCLDTLG HFADGVVGVY ECHNAGGNQE WALTKEKSVK HMDLCLTVVD RAPGSLIKLQ GCRENDSRQK WEQIEGNSKL RHVGSNLCLD SRTAKSGGLS VEVCGPALSQ QWKFTLNL. Catalyzes the initial reaction in O-linked oligosaccharide biosynthesi