Table I.

Conserved sequence motifs involved in substrate recognition and catalysis

Organism	C. lari	A. fulgidus	S. cerevisiae	H. sapiens	H. sapiens
Protein	PglBa	AglBa	STT3a	STT3A	STT3B
Sequon	D/EXNXT/S	NXT/S	NXT/S	NXT/S/C	NXT/S/C
Sequon bindingb
–2 position	R331	L379	D362	D363	D417
−1 position	T54	G45	E45	E47	E101
WWD motif
+2 position	W463	W550	W516	W525	W604
+2 position	W464	W551	W517	W526	W605
+2 position	D465	D552	D518	D527	D606
DK/MI motif
+2 position	I572	K618	K586	K595	K674
Active site
Mn++, Asn	D56	D47	D47	D49	D103
Mn++	D154	D161	D166	D167	D221
Mn++	D156	H163	E168	E169	E351
Mn++, Asn	E319	E360	E350	E351	E405
LLO binding
PPi	Y196	W215	W208	W209	W263
PPi	R375	R426	R404	R405	R459
NAc	Y468	H555	Y521	Y530	Y609
DGGK loop	D481GGK	N568PFQ	D534NNT	D543NNT	D662NNT

^aResidues and motifs in italics have been shown to be important for oligosaccharyltransferase activity in one or more of the following publications: PglB (Wacker et al. 2002; Lizak et al. 2011; Gerber et al. 2013; Barre et al. 2017; Napiorkowska et al. 2017); AglB (Matsumoto et al. 2013); yeast STT3 (Yan and Lennarz 2002b; Chavan et al. 2003; Li et al. 2005; Igura et al. 2008; Wild et al. 2018).

^bThe positions shown (−2, −1 and +2) are relative to the asparagine residue in a glycosylation site. PglB, AglB and STT3 residues involved in binding the asparagine residue in the sequon are listed in the active site section of this table.