Watson David C, Wakarchuk Warren W, Leclerc Sonia, Schur Melissa J, Schoenhofen Ian C, Young N Martin, Gilbert Michel
Human Health Therapeutics, National Research Council Canada, 100 Sussex Drive, Ottawa, ON, Canada K1A 0R6.
Department of Chemistry and Biology, Ryerson University, 350 Victoria St., Toronto, Ontario Canada M5B 2K3.
Glycobiology. 2015 Jul;25(7):767-73. doi: 10.1093/glycob/cwv017. Epub 2015 Apr 3.
Legionaminic acids (Leg) are bacterial analogs of neuraminic acid, with the same stereochemistry but different substituents at C5, C7 and C9. Hence they may be incorporated into useful analogs of sialoglycoconjugates, and we previously reported two sialyltransferases that could utilize cytidine monophosphate (CMP)-Leg5Ac7Ac for preparation of Leg glycoconjugates, which were resistant to sialidases [Watson DC, Leclerc S, Wakarchuk WW, Young NM. 2011. Enzymatic synthesis and properties of glycoconjugates with legionaminic acid as a replacement for neuraminic acid. Glycobiology. 21:99-108.]. These were the porcine ST3Gal1 and Pasteurella multocida sialyltransferases. We now report two additional sialyltransferases with superior Leg-transferase properties to the previous two. These are (i) a truncated form of a Photobacterium α2,6-sialyltransferase with an Ala-Met mutation in its active site, and (ii) an α2,3-sialyltransferase from Neisseria meningitidis MC58 with a higher transferase activity than the P. multocida enzyme, with either CMP-Neu5Ac or CMP-Leg5Ac7Ac as the donor. These enzymes will enable the production of useful Leg5Ac7Ac glycoconjugate derivatives with either α2,6 or α2,3 linkages and unique biological properties.
军团氨糖酸（Leg）是神经氨酸的细菌类似物，具有相同的立体化学结构，但在C5、C7和C9位具有不同的取代基。因此，它们可被掺入唾液酸糖缀合物的有用类似物中，并且我们之前报道了两种唾液酸转移酶，它们可以利用胞苷单磷酸（CMP）-Leg5Ac7Ac来制备对唾液酸酶具有抗性的Leg糖缀合物[Watson DC, Leclerc S, Wakarchuk WW, Young NM. 2011. 以军团氨糖酸替代神经氨酸的糖缀合物的酶促合成及性质。糖生物学。21:99 - 108。]。这两种酶是猪源ST3Gal1和多杀巴斯德氏菌唾液酸转移酶。我们现在报道另外两种唾液酸转移酶，它们具有比前两种酶更优的Leg转移酶性质。这两种酶分别是：（i）一种活性位点具有丙氨酸 - 甲硫氨酸突变的发光杆菌α2,6 - 唾液酸转移酶的截短形式，以及（ii）一种来自脑膜炎奈瑟菌MC58的α2,3 - 唾液酸转移酶，其转移酶活性高于多杀巴斯德氏菌的酶，以CMP - Neu5Ac或CMP - Leg5Ac7Ac作为供体。这些酶将能够生产具有α2,6或α2,3连接以及独特生物学性质的有用的Leg5Ac7Ac糖缀合物衍生物。
