A -Acetylglucosaminyltransferase

Two other structurally characterized transferases have the same or almost the same mode of Mn + coordination as Mn + in Bacillus subtilis glycosyltransferase SpsA described above. A-acetylglucosaminyltransferase I which serves as the gateway from oligomannose to hybrid and complex A-glycans and plays a critical role in mammalian development, has the same active site structure except the Mg + ion and the glycerol are not present. /3 1,3-Glucuronyltransferase I... 

WesterUnd U, Hagback P, Tidback B, Wiik L, BUxt O, Razi N, Norberg T. Synthesis of deoxy and acylamino derivatives of lactose and use of these for probing the active site of Neisseria meningitidis A-acetylglucosaminyltransferase. Carbohydr. Res. 2005 340 221-233. 

Kumar R, Yang J, Larsen RD, Stanley P. Qoning and expression 46. of A -acetylglucosaminyltransferase 1, the medial Golgi transferase that initiates complex Al-Unked carbohydrate formation. 47. Proc. Natl. Acad. Sci. U.S.A. 1990 87 9948-9952. 

Sasai K, Ikeda Y, Eguchi H, Tsuda T, Honke K, Taniguchi N. The achon of A-acetylglucosaminyltransferase-V is prevented by the bisecting GlcNAc residue at the catalyhc step. FEBS Lett. 2002 522(1-3) 151-155. 

CDG-type II syndrome [265,268] is a separate variant since it is characterized by a severe decrease in the activity of A-acetylglucosaminyltransferase II (UDP-GlcNAc a6-D-mannoside (3-l,2-A-acetylglucosaminyltransferase). As a consequence, the serotransferrin isoforms contain two truncated monoantennary glycans of which the primary structures are described in Fig. 19. 

Nakahara S, Salto T, Kondo N, Moriwaki K, Noda K, Ihara S, Takahashi M, Ide Y, Gu J, Inohara H, Katayama T, Tohyama M, Kubo T, Taniguchi N, Miyoshi E (2006) A secreted type of betal, 6-A -acetylglucosaminyltransferase V (GnT-V), a novel angiogenesis inducer, is regulated by gamma-secretase. Faseb J 20 2451-2459... 

Ioffe E, Stanley P. Mice lacking A-acetylglucosaminyltransferase I activity die at midgestation, revealing an essential role for complex or hybrid N-linked carbohydrates. Proc Natl Acad Sci USA 1994 91 728-732. 

Table 1. jV-acetylglucosaminyltransferases involved in /V-glycan synthesis. Abbreviations GnT, A-acetylglucosaminyltransferase Acc.No. is the EMBL/GenBank data base accession number. 

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