Journal of Glycobiology
Open Access
ISSN: 2168-958X
+44 1478 350008
ISSN: 2168-958X
+44 1478 350008
Chitra Mandal
Scientific Tracks Abstracts: J Glycobiol
Sialic acids (Sias) are typically present as terminal sugars in oligosaccharide moieties attached to glycoproteins. Pseudomonas
aeruginosa (PA), a gram-negative bacterium infects immuno-suppressed patients. We have established the presence
of linkage-specific Sias on PA. Sialic acid-binding immunoglobulin-type lectins (Siglecs) are present on all immune cells.
Sialylated PA (PA+Sias) binds to neutrophils through Sias-siglecs interactions. We have observed reduced oxidative burst, release
of elastase and decrease NETs formation thus indicating subversion of host innate immunity. Next, we have affinity purified and
sequenced twenty six sialoglycoproteins from PA+Sias. One such identified sialoglycoprotein is outer membrane porin protein D
(OprD), a beta-barrel shaped channel-forming protein. To establish the role of Sias on OprD proteins, they are purified from
sialylated (PA+Sias) and non-sialylated (PA-Sias) and their sialylation status are established. Profiling of glycan structures reveals
the presence of sialylated N- and O-glycans in OprD+Sias. Bioinformatics studies reveal that amongst four N-glycosylation sites
of OprD, Asn311 is present in the extracellular loop region having high solvent accessibility for its proper glycosylation. Core
glycan moieties can properly fit into Asn311 site with no spatial overlaps with suitable glycosidic conformations. Molecular
modeling studies suggest the presence of glycan structure with terminal bulky sialic acid hinders the channel passage of OprD
towards β-lactam antibiotic permeabilization. This might be one of the new mechanisms for β-lactam antibiotic resistance of
PA and thereby facilitating their survival in host. Our findings might help to open new avenue to design latest drug which can
enter cells freely even in presence of sialic acids.
Chitra Mandal completed her PhD at the age of 28 years from Indian Institute of Science, Bangalore and Post-Doctoral studies at University of Pennsylvania. She is
the Director of CSIR-Indian Institute of Chemical Biology, Kolkata, India and Sir J C Bose National Fellow, Head CSIR-Innovation Complex. She has published 150
research papers and holds 10 patents, guided 26 PhD students and transferred three technologies. She is an elected fellow of ‘The World Academy of Sciences, main
four academies in India. Main theme of her group is to understand the mystery of glycosylation of biomolecules and their potential applications in health and diseases.