Conserved sequence motifs in human TMTC1, TMTC2, TMTC3, and TMTC4, new O-mannosyltransferases from the GT-C/PMT clan, are rationalized as ligand binding sites

Table 3 Modelling the 3D structures of TMTCs

	TMTC1	TMTC2	TMTC3	TMTC4
Sequence identity with template (5EZM/5F15)	9.4%	10.6%	9.5%	11.3%
Modelled regions	23–456	1–336 & 393–474	4–428	17–464
Loop between TM6-TM7	240–257	207–220	209–231	242–262
Loop between TM9-TM10	393–406	411–419	*365–373	401–409
DUF1736 region (JM3)	284–358 (321–335)	247–321 (284–298)	258–331 (294–308)	292–366 (329–343)

The table provides the sequence identities of template 5EZM/5F15 with TMTCs, the range of the modelled regions, the longer loops between TM6-TM7 and TM8-TM9 compared with the templates, and location of DUF1736 along with JM3 (*residues 365–369 continue to be helical with TM9). TMTC2 has another unusual, longer cytoplasmic loop between TM8-TM9 (residues 337–392) which is not modelled in the absence of any template

ISSN: 1745-6150