9.B.225. The Mannosyl Transferase (MptB) Family 

The MtpB (formerly the DUF2029) family consists of many proteins which are sometimes annotated as DUF2029 or as mannosyltransferases. MtpB of Corynebacterium glutamicum has been characterized (Rainczuk et al. 2012). These proteins show weak similarity with members of the glycosyltransferase (GT39) family (TC# 9.B.142).  These two families may be related. It is not known if these transferases transport their carbohydrate substrates across the membrane.

This family belongs to the Glycosyl/Acyl Transferase (GAT) Superfamily.



Rainczuk, A.K., Y. Yamaryo-Botte, R. Brammananth, T.P. Stinear, T. Seemann, R.L. Coppel, M.J. McConville, and P.K. Crellin. (2012). The lipoprotein LpqW is essential for the mannosylation of periplasmic glycolipids in Corynebacteria. J. Biol. Chem. 287: 42726-42738.


TC#NameOrganismal TypeExample

Estabilshed α-1,6 mannosyltransferase B, MptB of 602 aas and 11 TMSs. Involved in the initiation of core alpha-(1,6) mannan biosynthesis of lipomannan (LM-A) and multi-mannosylated polymer (LM-B), extending triacylatedphosphatidyl-myo-inositol dimannoside (Ac1PIM2) and mannosylated glycolipid, 1,2-di-O-C16/C18:1-(alpha-D-mannopyranosyl)-(1->4)-(alpha-D-glucopyranosyluronic acid)-(1->3)-glycerol (Man1GlcAGroAc2), respectively. Catalyzes the addition of alpha-(1->6)-mannosyl residues (Rainczuk et al. 2012).

MptB of Corynebacterium glutamicum


Uncharacterized DUF2029 domain protein of 521 aas and 11 TMSs.

UP of Nakamurella lactea


Uncharacterized putative α-1,6 mannosyltransferase of 541 aas and 12 TMSs. 

UP of Kibdelosporangium aridum


Uncharacterized DUF2029 domain protein of 475 aas and 11 TMSs.

UP of Solirubrobacter soli


Uncharacterized putative mannosyltransferase of 453 aas and 12 TMSs.

UP of Kriegella aquimaris


Uncharacterized protein of 551 aas and 16 TMSs

UP of Thermogemmatispora carboxidivorans


The uncharacterized DUF2029 domain-containing protein of 438 aas and 11 TMSs.

UP of Lishizhenia tianjinensis


Uncharacterized protein of 424 aas and 10 TMSs

UP of Indibacter alkaliphilus


TC#NameOrganismal TypeExample

Uncharacterized protein of 457 aas and 9 putative TMSs. Distantly related to 8.A.95. May be a 4-amino-4-deoxy-L-arabinose transferase or related glycosyltransferase of the PMT family.

UP of Aeromonas salmonicida


TC#NameOrganismal TypeExample