Chemoenzymatic Total Synthesis of GM3 Gangliosides Containing Different Sialic Acid Forms and Various Fatty Acyl Chains

Abstract

Gangliosides are sialic acid-containing glycosphingolipids that have been found in the cell membranes of all vertebrates. Their important biological functions are contributed by both the glycan and the ceramide lipid components. GM3 is a major ganglioside and a precursor for many other more complex gangliosides. To obtain structurally diverse GM3 gangliosides containing various sialic acid forms and different fatty acyl chains in low cost, an improved process was developed to chemically synthesize lactosyl sphingosine from an inexpensive L-serine derivative. It was then used to obtain GM3 sphingosines from diverse modified sialic acid precursors by an efficient one-pot multienzyme sialylation system containing Pasteurella multocida sialyltransferase 3 (PmST3) with in situ generation of sugar nucleotides. A highly effective chemical acylation and facile C18cartridge purification process was then used to install fatty acyl chains of varying lengths and different modifications. The chemoenzymatic method represents a powerful total synthetic strategy to access a library of structurally defined GM3 gangliosides to explore their functions.

Chemoenzymatic synthesis and biological evaluation of ganglioside GM3 and lyso-GM3 as potential agents for cancer therapy

“…Here, two natural occurring sialic acid forms Neu5Ac and Neu5Gc and one nonnatural Neu5TFA are introduced into the structures of the target ganglioside glycans. Both Neu5Ac (in humans and animals) and Neu5Gc (in animals and small amounts in humans) are common sialic acid forms found in gangliosides [32,33]. Its unique property of resistance to sialidases makes the glycans containing Neu5TFA moiety interesting for biofunctional studies.…”

One-Pot Enzymatic Synthesis and Biological Evaluation of Ganglioside GM3 Derivatives as Potential Cancer Immunotherapeutics

“…Recently, the development of enzymatic methods has paved the way to synthesizing these synthetically challenging molecules. − Yu and Santra et al established a one-pot two-enzyme system containing Neisseria meningitides CMP-sialic acid synthetase (NmCSS) and Pasteurella multocida α 2–3-sialyltransferase 3 (PmST3) and successfully obtained GM3 sphingosine (GM3βSph) lacking the fatty acyl chain from lactose-sphingosine and monosaccharide N -acetylneuraminic acid (Neu5Ac) . Compared to laborious chemical methods, highly selective and specific enzymatic synthesis has proven to be a promising method by avoiding the necessity of numerous protecting group strategies .…”

“…Compared to laborious chemical methods, highly selective and specific enzymatic synthesis has proven to be a promising method by avoiding the necessity of numerous protecting group strategies . In this regard, enzymatic synthesis is much more favored. , However, methods reported by Chen’s , and Meng’s groups involved the synthesis of lactose-sphingosine with 11 and 10 chemical steps, respectively. The acylation of lyso-GM3 and derivatives with a fatty acid was also performed by chemical synthesis.…”

Chemoenzymatic Synthesis of Globo‐series Glycosphingolipids and Evaluation of Their Immunosuppressive Activities

“…[22] Therefore, synthesizing chemically pure GSLs with different lengths of fatty acid might be crucial for elucidating the proper biological roles of GSLs. [23] Several research groups have proposed both enzymatic and chemoenzymatic methods of preparing globo-series glycans such as SSEA-3 (Gb5), SSEA-4 (MSGb5), Globo H, and DSGb5. [24][25][26][27] However, only a few total chemical syntheses of globo-series GSL are available, and the requirement for extensive selective protection/deprotection steps and stereoselective conversion of glycosyl donors to GSLs result in a large number of steps and low overall yield.…”

“…This is partly due to the challenging and time‐consuming task of synthesizing these highly complex GSL molecules; there are only a few reports on semisynthetic methods for producing glycolipids [22] . Therefore, synthesizing chemically pure GSLs with different lengths of fatty acid might be crucial for elucidating the proper biological roles of GSLs [23] …”