Glycans
Encyclopedia
The term glycan refers to a polysaccharide
or oligosaccharide
. Glycans usually consist solely of O-glycosidic linkage
s of monosaccharides. For example, cellulose is a glycan (or, to be more specific, a glucan
) composed of beta-1,4-linked D-glucose, and chitin is a glycan composed of beta-1,4-linked N-acetyl-D-glucosamine. Glycans can be homo- or heteropolymers of monosaccharide residues, and can be linear or branched. Glycan may also be used to refer to the carbohydrate
portion of a glycoconjugate, such as a glycoprotein
, glycolipid
, or a proteoglycan
.
in the sequon
. The sequon is a Asn-X-Ser or Asn-X-Thr sequence, where X is any amino acid except proline
and may be composed of N-acetyl galactosamine, galactose
, neuraminic acid
, N-acetylglucosamine
, fructose
, mannose
, fucose
, and other monosaccharides.
unit assembled in the cytoplasm
and endoplasmic reticulum
. First, two N-acetyl glucosamine residues are attached to dolichol phosphate, a lipid, on the external side of the endoplasmic reticulum membrane. Five mannose residues are then added to this structure. At this point, the partially finished core glycan is flipped across the endoplasmic reticulum membrane, so that it is now located within the reticular lumen. Assembly then continues within the endoplasmic reticulum, with the addition of four more mannose residues. Finally, three glucose residues are added to this structure. Following full assembly, the glycan is transferred en bloc by the glycosyltransferase
oligosaccharyltransferase
to a nascent peptide chain, within the reticular lumen. This core structure of N-linked glycans, thus, consists of 14 residues (3 glucose, 9 mannose, and 2 N-acetylglucosamine).
Image: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.469
Dark squares are N-acetyl-glucosamine; light circles are mannose; dark triangles are glucose.
. Modification reactions may involve the addition of a phosphate or acetyl group onto the sugars, or the addition of new sugars, such as neuraminic acid
. Processing and modification of N-linked glycans within the Golgi does not follow a linear pathway. As a result, many different variations of N-linked glycan structure are possible, depending on enzyme activity in the Golgi.
and calreticulin
, bind to the three glucose residues present on the core N-linked glycan. These chaperone proteins then serve to aid in the folding of the protein that the glycan is attached to. Following proper folding, the three glucose residues are removed, and the glycan moves on to further processing reactions. If the protein fails to fold properly, the three glucose residues are reattached, allowing the protein to re-associate with the chaperones. This cycle may repeat several times until a protein reaches its proper conformation. If a protein repeatedly fails to properly fold, it is excreted from the endoplasmic reticulum and degraded by cytoplasmic proteases.
N-linked glycans also contribute to protein folding by steric effects. For example, cysteine
residues in the peptide may be temporarily blocked from forming disulfide bonds with other cysteine residues, due to the size of a nearby glycan. Therefore, the presence of a N-linked glycan allows the cell to control which cysteine residues will form disulfide bonds.
N-linked glycans also play an important role in cell-cell interactions. For example, tumour cells make N-linked glycans that are abnormal. These are recognized by the CD337 receptor on Natural Killer cell
s as a sign that the cell in question is cancerous.
The targeting of degradative lysosomal enzymes is also accomplished by N-linked glycans. The modification of an N-linked glycan with a mannose-6-phosphate
residue serves as a signal that the protein to which this glycan is attached should be moved to the lysosome. This recognition and trafficking of lysosomal enzymes by the presence of mannose-6-phosphate is accomplished by two proteins: CI-MPR (cation-independent mannose-6-phosphate receptor
) and CD-MPR (cation-dependent mannose-6-phosphate receptor).
or threonine
residue of a peptide chain in the Golgi apparatus. Unlike with N-linked glycans, there is as of yet no known consensus sequence. However, the placement of a proline
residue at either -1 or +3 relative to the serine or threonine is favourable for O-linked glycosylation.
Images:
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.561 : Core 1 and Core 2 generation. White square = N-acetyl-galactosamine; black circle = galactose; Black square = N-acetly-glucosamine. Note: There is a mistake in this diagram. The bottom square should always be white in each image, not black.
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.562 : Core 3 and Core 4 generation.
A common structural theme in O-linked glycans is the addition of polylactosamine units to the various core structures. These are formed by the repetitive addition of galactose and N-acetyl-glucosamine units. Polylactosamine chains on O-linked glycans are often capped by the addition of a sialic acid
residue (similar to neuraminic acid). If a fucose
residue is also added, to the next to penultimate residue, a Sialyl lewis x
(SLex)) structure is formed.
is important in ABO
blood antigen determination.
SLex is also important to proper immune response. E-selectin
release from Weibel-Palade bodies, on blood vessel epithelial cells, can be induced by a number of factors. One such factor is the response of the epithelial cell to certain bacterial molecules, such as peptidoglycan
. E-selectin binds to the SLex structure that is present on neutrophils in the blood stream, and helps to mediate the extravasation
of these cells into the surrounding tissue during an infection.
O-linked glycans, in particular, mucin, have been found to be important in developing normal intestinal microflora. Certain strains of intestinal bacteria bind specifically to mucin, allowing them to colonize the intestine.
Examples of O-linked glycoprotein
s are:
Polysaccharide
Polysaccharides are long carbohydrate molecules, of repeated monomer units joined together by glycosidic bonds. They range in structure from linear to highly branched. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure,...
or oligosaccharide
Oligosaccharide
An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars...
. Glycans usually consist solely of O-glycosidic linkage
Glycosidic bond
In chemistry, a glycosidic bond is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate....
s of monosaccharides. For example, cellulose is a glycan (or, to be more specific, a glucan
Glucan
A glucan molecule is a polysaccharide of D-glucose monomers linked by glycosidic bonds.Many beta-glucans are medically important.-Types:The following are glucans:-Alpha:...
) composed of beta-1,4-linked D-glucose, and chitin is a glycan composed of beta-1,4-linked N-acetyl-D-glucosamine. Glycans can be homo- or heteropolymers of monosaccharide residues, and can be linear or branched. Glycan may also be used to refer to the carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
portion of a glycoconjugate, such as a glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
, glycolipid
Glycolipid
Glycolipids are lipids with a carbohydrate attached. Their role is to provide energy and also serve as markers for cellular recognition.-Metabolism:...
, or a proteoglycan
Proteoglycan
Proteoglycans are proteins that are heavily glycosylated. The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan chain. The point of attachment is a Ser residue to which the glycosaminoglycan is joined through a tetrasaccharide bridge...
.
Glycans and Proteins
Glycans can be found attached to proteins as in glycoproteins and proteoglycans. In general, they are found on the exterior surface of cells. O- and N-linked glycans are very common in eukaryotes but may also be found, although less commonly, in prokaryotes.Introduction
N-Linked glycans are found attached to the R-group nitrogen (N) of asparagineAsparagine
Asparagine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side-chain's functional group. It is not an essential amino acid...
in the sequon
Sequon
A sequon is a sequence of three consecutive amino acids in a proteinthat can serve as the attachment site to a polysaccharide called anN-linked-Glycan. This is a polysaccharidelinked to the protein via the nitrogen atom in the side chain of...
. The sequon is a Asn-X-Ser or Asn-X-Thr sequence, where X is any amino acid except proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...
and may be composed of N-acetyl galactosamine, galactose
Galactose
Galactose , sometimes abbreviated Gal, is a type of sugar that is less sweet than glucose. It is a C-4 epimer of glucose....
, neuraminic acid
Neuraminic acid
Neuraminic acid is a 9-carbon monosaccharide, a derivative of a ketononose. Neuraminic acid may be visualized as the product of an aldol-condensation product of pyruvic acid and D-mannosamine...
, N-acetylglucosamine
N-Acetylglucosamine
N-Acetylglucosamine is a monosaccharide derivative of glucose. It is an amide between glucosamine and acetic acid...
, fructose
Fructose
Fructose, or fruit sugar, is a simple monosaccharide found in many plants. It is one of the three dietary monosaccharides, along with glucose and galactose, that are absorbed directly into the bloodstream during digestion. Fructose was discovered by French chemist Augustin-Pierre Dubrunfaut in 1847...
, mannose
Mannose
Mannose is a sugar monomer of the aldohexose series of carbohydrates. Mannose is a C-2 epimer of glucose. It is not part of human metabolism, but is a component of microbial cell walls, and is therefore a target of the immune system and also of antibiotics....
, fucose
Fucose
Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N-linked glycans on the mammalian, insect and plant cell surface, and is the fundamental sub-unit of the fucoidan polysaccharide...
, and other monosaccharides.
Assembly
In eukaryotes, N-linked glycans are derived from a core 14-sugarSugar
Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...
unit assembled in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...
and endoplasmic reticulum
Endoplasmic reticulum
The endoplasmic reticulum is an organelle of cells in eukaryotic organisms that forms an interconnected network of tubules, vesicles, and cisternae...
. First, two N-acetyl glucosamine residues are attached to dolichol phosphate, a lipid, on the external side of the endoplasmic reticulum membrane. Five mannose residues are then added to this structure. At this point, the partially finished core glycan is flipped across the endoplasmic reticulum membrane, so that it is now located within the reticular lumen. Assembly then continues within the endoplasmic reticulum, with the addition of four more mannose residues. Finally, three glucose residues are added to this structure. Following full assembly, the glycan is transferred en bloc by the glycosyltransferase
Glycosyltransferase
Glycosyltransferases are enzymes that act as a catalyst for the transfer of a monosaccharide unit from an activated nucleotide sugar to a glycosyl acceptor molecule, usually an alcohol....
oligosaccharyltransferase
Oligosaccharyltransferase
Oligosaccharyltransferase or OST is a membrane protein complex that transfers a 14-sugar oligosaccharide from dolichol to nascent protein. It is a type of glycosyltransferase...
to a nascent peptide chain, within the reticular lumen. This core structure of N-linked glycans, thus, consists of 14 residues (3 glucose, 9 mannose, and 2 N-acetylglucosamine).
Image: http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.469
Dark squares are N-acetyl-glucosamine; light circles are mannose; dark triangles are glucose.
Processing, modification, and diversity
Once transferred to the nascent peptide chain, N-linked glycans, in general, undergo extensive processing reactions, whereby the three glucose residues are removed, as well as several mannose residues, depending on the N-linked glycan in question. The removal of the glucose residues is dependent on proper protein folding. These processing reactions occur in the Golgi apparatusGolgi apparatus
The Golgi apparatus is an organelle found in most eukaryotic cells. It was identified in 1898 by the Italian physician Camillo Golgi, after whom the Golgi apparatus is named....
. Modification reactions may involve the addition of a phosphate or acetyl group onto the sugars, or the addition of new sugars, such as neuraminic acid
Neuraminic acid
Neuraminic acid is a 9-carbon monosaccharide, a derivative of a ketononose. Neuraminic acid may be visualized as the product of an aldol-condensation product of pyruvic acid and D-mannosamine...
. Processing and modification of N-linked glycans within the Golgi does not follow a linear pathway. As a result, many different variations of N-linked glycan structure are possible, depending on enzyme activity in the Golgi.
Functions and importance
N-linked glycans are extremely important in proper protein folding in eukaryotic cells. Chaperone proteins in the endoplasmic reticulum, such as calnexinCalnexin
Calnexin is a 90kDa integral protein of the endoplasmic reticulum . It consists of a large N-terminal calcium-binding lumenal domain, a single transmembrane helix and a short , acidic cytoplasmic tail....
and calreticulin
Calreticulin
Calreticulin also known as calregulin, CRP55, CaBP3, calsequestrin-like protein, and endoplasmic reticulum resident protein 60 is a protein that in humans is encoded by the CALR gene....
, bind to the three glucose residues present on the core N-linked glycan. These chaperone proteins then serve to aid in the folding of the protein that the glycan is attached to. Following proper folding, the three glucose residues are removed, and the glycan moves on to further processing reactions. If the protein fails to fold properly, the three glucose residues are reattached, allowing the protein to re-associate with the chaperones. This cycle may repeat several times until a protein reaches its proper conformation. If a protein repeatedly fails to properly fold, it is excreted from the endoplasmic reticulum and degraded by cytoplasmic proteases.
N-linked glycans also contribute to protein folding by steric effects. For example, cysteine
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
residues in the peptide may be temporarily blocked from forming disulfide bonds with other cysteine residues, due to the size of a nearby glycan. Therefore, the presence of a N-linked glycan allows the cell to control which cysteine residues will form disulfide bonds.
N-linked glycans also play an important role in cell-cell interactions. For example, tumour cells make N-linked glycans that are abnormal. These are recognized by the CD337 receptor on Natural Killer cell
Natural killer cell
Natural killer cells are a type of cytotoxic lymphocyte that constitute a major component of the innate immune system. NK cells play a major role in the rejection of tumors and cells infected by viruses...
s as a sign that the cell in question is cancerous.
The targeting of degradative lysosomal enzymes is also accomplished by N-linked glycans. The modification of an N-linked glycan with a mannose-6-phosphate
Mannose-6-phosphate
Mannose-6-phosphate is a molecule bound by lectin in the immune system. M6P is converted to fructose 6-phosphate by mannose phosphate isomerase....
residue serves as a signal that the protein to which this glycan is attached should be moved to the lysosome. This recognition and trafficking of lysosomal enzymes by the presence of mannose-6-phosphate is accomplished by two proteins: CI-MPR (cation-independent mannose-6-phosphate receptor
Mannose 6-phosphate receptor
In the fields of biochemistry and cell biology, mannose 6-phosphate receptors are proteins that bind newly synthesized lysosomal hydrolases in the trans-Golgi network and deliver them to pre-lysosomal compartments. There are two different MPRs, one of ~300kDa and a smaller, dimeric receptor of...
) and CD-MPR (cation-dependent mannose-6-phosphate receptor).
Introduction
In eukaryotes, O-linked glycans are assembled one sugar at a time on a serineSerine
Serine is an amino acid with the formula HO2CCHCH2OH. It is one of the proteinogenic amino acids. By virtue of the hydroxyl group, serine is classified as a polar amino acid.-Occurrence and biosynthesis:...
or threonine
Threonine
Threonine is an α-amino acid with the chemical formula HO2CCHCHCH3. Its codons are ACU, ACA, ACC, and ACG. This essential amino acid is classified as polar...
residue of a peptide chain in the Golgi apparatus. Unlike with N-linked glycans, there is as of yet no known consensus sequence. However, the placement of a proline
Proline
Proline is an α-amino acid, one of the twenty DNA-encoded amino acids. Its codons are CCU, CCC, CCA, and CCG. It is not an essential amino acid, which means that the human body can synthesize it. It is unique among the 20 protein-forming amino acids in that the α-amino group is secondary...
residue at either -1 or +3 relative to the serine or threonine is favourable for O-linked glycosylation.
Assembly
The first monosaccharide attached in the synthesis of O-linked glycans is N-acetyl-galactosamine. After this, several different pathways are possible. A Core 1 structure is generated by the addition of galactose. A Core 2 structure is generated by the addition of N-acetyl-glucosamine to the N-acetyl-galactosamine of the Core 1 structure. Core 3 structures are generated by the addition of a single N-acetyl-glucosamine to the original N-acetyl-galactosamine. Core 4 structures are generated by the addition of a second N-acetly-glucosamine to the Core 3 structure. Other core structures are possible, though less common.Images:
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.561 : Core 1 and Core 2 generation. White square = N-acetyl-galactosamine; black circle = galactose; Black square = N-acetly-glucosamine. Note: There is a mistake in this diagram. The bottom square should always be white in each image, not black.
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=glyco.figgrp.562 : Core 3 and Core 4 generation.
A common structural theme in O-linked glycans is the addition of polylactosamine units to the various core structures. These are formed by the repetitive addition of galactose and N-acetyl-glucosamine units. Polylactosamine chains on O-linked glycans are often capped by the addition of a sialic acid
Sialic acid
Sialic acid is a generic term for the N- or O-substituted derivatives of neuraminic acid, a monosaccharide with a nine-carbon backbone. It is also the name for the most common member of this group, N-acetylneuraminic acid...
residue (similar to neuraminic acid). If a fucose
Fucose
Fucose is a hexose deoxy sugar with the chemical formula C6H12O5. It is found on N-linked glycans on the mammalian, insect and plant cell surface, and is the fundamental sub-unit of the fucoidan polysaccharide...
residue is also added, to the next to penultimate residue, a Sialyl lewis x
Sialyl lewis x
Sialyl LewisX, also known as sialyl LeX and SLeX, is a tetrasaccharide carbohydrate that is usually attached to O-glycans on the surface of cells. It is known to play a vital role in cell-to-cell recognition processes. It is also the means in which an egg attracts sperm - first to stick to it,...
(SLex)) structure is formed.
Functions and importance
Sialyl lewis xSialyl lewis x
Sialyl LewisX, also known as sialyl LeX and SLeX, is a tetrasaccharide carbohydrate that is usually attached to O-glycans on the surface of cells. It is known to play a vital role in cell-to-cell recognition processes. It is also the means in which an egg attracts sperm - first to stick to it,...
is important in ABO
Abo
Abo may refer to:* ABO blood group system, a human blood type and blood group system** ABO , enzyme encoded by the ABO gene that determines the ABO blood group of an individual* Abo of Tiflis , an Arab East Orthodox Catholic saint...
blood antigen determination.
SLex is also important to proper immune response. E-selectin
Selectin
Selectins are a family of cell adhesion molecules . All selectins are single-chain transmembrane glycoproteins that share similar properties to C-type lectins due to a related amino terminus and calcium-dependent binding...
release from Weibel-Palade bodies, on blood vessel epithelial cells, can be induced by a number of factors. One such factor is the response of the epithelial cell to certain bacterial molecules, such as peptidoglycan
Peptidoglycan
Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of bacteria , forming the cell wall. The sugar component consists of alternating residues of β- linked N-acetylglucosamine and N-acetylmuramic acid...
. E-selectin binds to the SLex structure that is present on neutrophils in the blood stream, and helps to mediate the extravasation
Extravasation
Extravasation is the accidental administration of intravenously infused medicinal drugs into the surrounding tissue, either by leakage , or direct exposure...
of these cells into the surrounding tissue during an infection.
O-linked glycans, in particular, mucin, have been found to be important in developing normal intestinal microflora. Certain strains of intestinal bacteria bind specifically to mucin, allowing them to colonize the intestine.
Examples of O-linked glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
s are:
- GlycophorinGlycophorinA Glycophorin is a sialoglycoprotein of the membrane of a red blood cell. It is a membrane-spanning protein and carries sugar molecules. It is heavily glycosylated . Glycophorins are rich in sialic acid, which gives the red cells a very hydrophilic-charged coat...
, a protein in erythrocyte cell membranes - MucinMucinMucins are a family of high molecular weight, heavily glycosylated proteins produced by epithelial tissues in most metazoans. Mucins' key characteristic is their ability to form gels; therefore they are a key component in most gel-like secretions, serving functions from lubrication to cell...
, a protein in salivaSalivaSaliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...
involved in formation of dental plaqueDental plaqueDental plaque is a biofilm, usually a pale yellow, that develops naturally on the teeth. Like any biofilm, dental plaque is formed by colonizing bacteria trying to attach themselves to a smooth surface... - NotchNotch signalingThe notch signaling pathway is a highly conserved cell signaling system present in most multicellular organisms.Notch is present in all metazoans, and mammals possess four different notch receptors, referred to as NOTCH1, NOTCH2, NOTCH3, and NOTCH4. The notch receptor is a single-pass...
, a transmembrane receptor involved in development and cell fate decisions - ThrombospondinThrombospondinThrombospondins are secreted proteins with antiangiogenic abilities. TSP was discovered by Nancy L. Baenziger.-Types:The thrombospondins are a family of multifunctional proteins...
- Factor VIIFactor VIIFactor VII is one of the proteins that causes blood to clot in the coagulation cascade. It is an enzyme of the serine protease class. A recombinant form of human factor VIIa has U.S. Food and Drug Administration approval for uncontrolled bleeding in hemophilia patients...
- Factor IXFactor IXFactor IX is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes hemophilia B. It was discovered in 1952 after a young boy named Stephen Christmas was found to be lacking this exact factor, leading to...
- Urinary type plasminogen activatorPlasminogen activatorA plasminogen activator is a serine protease which converts plasminogen to plasmin, thus promoting fibrinolysis.Types include:* Tissue plasminogen activator* Urokinase...
Glycosaminoglycans
Another type of cellular glycan is the glycosaminoglycans. These comprise 2-aminosugars linked in an alternating fashion with uronic acids, and include polymers such as heparin, heparan sulfate, chondroitin, keratin, and dermatan. Some glycosaminoglycans are found attached to the cell surface, where they are linked through a single xylosyl residue to a protein.- heparinHeparinHeparin , also known as unfractionated heparin, a highly sulfated glycosaminoglycan, is widely used as an injectable anticoagulant, and has the highest negative charge density of any known biological molecule...
- heparan sulfateHeparan sulfateHeparan sulfate is a linear polysaccharide found in all animal tissues. It occurs as a proteoglycan in which two or three HS chains are attached in close proximity to cell surface or extracellular matrix proteins...
- dermatan
- keratinKeratinKeratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
- chondroitinChondroitinChondroitin is a chondrin derivative.Types include:* Chondroitin sulfate* Dermatan sulfate...
Resources
- GlycoSuiteDB, glycan database by Swiss Institute of BioinformaticsSwiss Institute of BioinformaticsThe Swiss Institute of Bioinformatics is an academic not-for-profit foundation which federates bioinformatics activities throughout Switzerland...
- The Consortium for Functional GlycomicsConsortium for Functional GlycomicsThe Consortium for Functional Glycomics is a large research initiative funded in 2001 by a glue grant from the National Institute of General Medical Sciences to “define paradigms by which protein-carbohydrate interactions mediate cell communication”...
(CFG) is a non-profit research initiative comprising eight core facilities and 500+ participating investigators that work together to develop resources and services and make them available to the scientific community free of charge. The data generated by these resources are captured in databases accessible through the Functional Glycomics Gateway, a web resource maintained through a partnership between the CFG and Nature Publishing GroupNature Publishing GroupNature Publishing Group is an international publishing company that publishes academic journals, online databases, and services across the life, physical, chemical and applied sciences and clinical medicine...
.