Glycans and Glycobiology (nano) Flashcards
Musins
In exam
Role, lung
Perlecan
Read
Background
Cell defence
Cell Cell adhesion
Traffic: glycoprotein gets stuck in cell, molecules need to penetrate this layer
Application in cancer and infertility
Decoration on cell : whats on its surface, usually a lipid membrane, often theres glycosylated transmembrane protein which are usually “sensors” for the external environment
Glycans and polysaccharides
Glycans: monosacs and sugars linked glyccosidically
Usually O-linked glycosidic links
Class of glycoconjugates
Glycolipids
N linked glycoproteins
O linked glycoproteins
Serine and Therine
All linked to sugar molecules
N glycosidic bond
Aspartine (Asn) is attached, amino acid side chain
O linked
Linked through serine residues
Scaffolding proteins
They all have the same genome, but can be decorated to have a differential role
Lectins
They are integral membrane proteins, carbohydrate recognition domain (CRD) is located in extracellular or luminal spaces.
Intracellular lectins: recognise core sugar structures common to many glycoproteins
main role: control/regulate flow of glycoproteins through secretory pathway.
Extracellular lectins
Innate immunity internalization of pathogens cell adhedsion antigen embryo implantation
Glycoprotein receptor
A linear structure that recognise foreign bodies, used to stick and cleave before the cell is attacked.
Glycan assembly
Synthesis of lipid precursor, transfered to ER for trimmming of sugar residues, transferred to golgi for modification and excreted
Glycosyltransferase Gtf
Class of enzyme that catalyse sugar from donor to receptor protein.
Forms glycosidic bonds
Very strict specificity, only 1 sugar - 1 receptor - 1 linkage
Adds monosacs onto sugars, proteins and lipid with perfect specificity.
Overexpressed glycoproteins in the lungs so they catch foreign bodies and excrete.
O glycosylation
2 groups:
Musins - small glycan structure
Proteoglycan
