Symbol Nomenclature for Glycans (SNFG)

Standardization in drawing glycan structures is essential for efficient communication. The tools and methodology illustrated here have become widely accepted by the scientific community. Use of these symbols to represent monosaccharides is now strongly recommended for all manuscripts submitted to major journals and other publications.

Citation: Symbol Nomenclature for Graphical Representation of Glycans, Glycobiology 25: 1323-1324, 2015. Citation link (PMID 26543186).

History of the SNFG

The SNFG Discussion Group

Organizations and Publications Adopting SNFG

Software tools supporting SNFG

  1. 3D-Symbol Nomenclature for Glycans (3D-SNFG): Create 3D atomic models of glycans
    Direct weblink | Citation link.
  2. DrawGlycan SNFG: Convert IUPAC input strings to sketches of glycans and glycopeptides
    Direct weblink | App download | Citation link.
  3. GlycanBuilder2-SNFG: GlycanBuilder updated to handle SNFG
    Direct weblink | App download | Citation link.

Symbol Nomenclature

Downloadable files: Drawing format | Presentation/Slide format | Notes | Examples

Each symbol represents a specific monosaccharide or class of monosaccharides found in nature. Hover over Symbol with pointer to see the full monosaccharide name. Click on a symbol to link to the corresponding PubChem entry. Symbols can also be copied with embedded links from the table using right/control-click or highlight-copy (highlight a symbol, then control-c [on pc], or command⌘-c [on mac]). However links may not copy in some browsers. Symbols with embedded PubChem URLs are therefore also available in the presentation/slide format attachments (see links above the table). A high-quality SVG object file is also provided.

Table 1. Monosaccharide symbol nomenclature

SHAPEWhite
(Generic)
BlueGreenYellowOrangePinkPurpleLight BlueBrownRed
Filled CircleImage for Hexose
Hexose
Symbol for D-Glucose
Glc
Symbol for D-Mannose
Man
Symbol for D-Galactose
Gal
Symbol for D-Gulose
Gul
Symbol for L-Altrose
Alt
Symbol for D-Allose
All
Symbol for D-Talose
Tal
Symbol for L-Idose
Ido
Filled SquareImage for HexNAc
HexNAc
Symbol for N-Acetyl-D-glucosamine
GlcNAc
Symbol for N-Acetyl-D-mannosamine
ManNAc
Symbol for N-Acetyl-D-galactosamine
GalNAc
Symbol for N-Acetyl-D-gulosamine
GulNAc
Symbol for N-Acetyl-L-altrosamine
AltNAc
Symbol for N-Acetyl-D-allosamine
AllNAc
Symbol for N-Acetyl-D-talosamine
TalNAc
Symbol for N-Acetyl-L-idosamine
IdoNAc
Crossed SquareImage for Hexosamine
Hexosamine
Symbol for D-Glucosamine
GlcN
Symbol for D-Mannosamine
ManN
Symbol for D-Galactosamine
GalN
Symbol for D-Gulosamine
GulN
Symbol for L-Altrosamine
AltN
Symbol for D-Allosamine
AllN
Symbol for D-Talosamine
TalN
Symbol for L-Idosamine
IdoN
Divided DiamondImage for Hexuronate
Hexuronate
Symbol for D-Glucuronic acid
GlcA
Symbol for D-Mannuronic acid
ManA
Symbol for D-Galacturonic acid
GalA
Symbol for D-Guluronic acid
GulA
Symbol for L-Altruronic acid
AltA
Symbol for D-Alluronic acid
AllA
Symbol for D-Taluronic acid
TalA
Symbol for L-Iduronic acid
IdoA
Filled TriangleImage for Deoxyhexose
Deoxyhexose
Symbol for D-Quinovose
Qui
Symbol for L-Rhamnose
Rha
Symbol for 6-Deoxy-D-gulose
6dGul
Symbol for 6-Deoxy-L-altrose
6dAlt
Symbol for 6-Deoxy-D-talose
6dTal
Symbol for L-Fucose
Fuc
Divided TriangleImage for DeoxyhexNAc
DeoxyhexNAc
Symbol for N-Acetyl-D-quinovosamine
QuiNAc
Symbol for N-Acetyl-L-rhamnosamine
RhaNAc
Symbol for N-Acetyl-6-deoxy-L-altrosamine
6dAltNAc
Symbol for N-Acetyl-6-deoxy-D-talosamine
6dTalNAc
Symbol for N-Acetyl-L-fucosamine
FucNAc
Flat RectangleImage for Di-deoxyhexose
Di-deoxyhexose
Symbol for Olivose
Oli
Symbol for Tyvelose
Tyv
Symbol for Abequose
Abe
Symbol for Paratose
Par
Symbol for D-Digitoxose
Dig
Symbol for Colitose
Col
Filled StarImage for Pentose
Pentose
Symbol for L-Arabinose
Ara
Symbol for D-Lyxose
Lyx
Symbol for D-Xylose
Xyl
Symbol for D-Ribose
Rib
Filled DiamondImage for Deoxynonulosonate
Deoxynonulosonate
Symbol for 3-Deoxy-D-glycero-D-galacto-nonulosonic acid
Kdn
Symbol for N-Acetylneuraminic acid
Neu5Ac
Symbol for N-Glycolylneuraminic acid
Neu5Gc
Symbol for Neuraminic acid
Neu
Symbol for Sialic acid
Sia
Flat DiamondImage for Di-deoxynonulosonate
Di-deoxynonulosonate
Symbol for Pseudaminic acid
Pse
Symbol for Legionaminic acid
Leg
Symbol for Acinetaminic acid
Aci
Symbol for 4-Epilegionaminic acid
4eLeg
Flat HexagonImage for Unknown sacchride
Unknown
Symbol for Bacillosamine
Bac
Symbol for L-glycero-D-manno-Heptose
LDmanHep
Symbol for 3-Deoxy-D-manno-octulosonic acid
Kdo
Symbol for 3-Deoxy-D-lyxo-heptulosaric acid
Dha
Symbol for D-glycero-D-manno-Heptose
DDmanHep
Symbol for N-Acetylmuramic acid
MurNAc
Symbol for N-Glycolylmuramic acid
MurNGc
Symbol for Muramic acid
Mur
PentagonImage for Assigned sacchride
Assigned
Symbol for L-Apiose
Api
Symbol for D-Fructose
Fru
Symbol for D-Tagatose
Tag
Symbol for L-Sorbose
Sor
Symbol for D-Psicose
Psi

Notes

  1. General: The monosaccharide symbols presented here are from the Third Edition of the Essentials of Glycobiology. They are extended from the symbols in the Second Edition (Figure 1.5, Second Edition) to cover a wider range of monosaccharides found in nature. While previous versions allowed conversion of monosaccharide symbols to black and white representation, this is no longer possible. A listing of abbreviated, full, and complete names of all assigned monosaccharides is shown in Table 3. Selected examples depicting SNFG usage are presented below the footnotes, for various living organisms.
  2. Drawing recommendations: All downloadable symbols follow CMYK colors as shown in Table 2, which were generated in Adobe Illustrator. Recommended CMYK to RGB conversion is also provided. While there is no hard rule, glycans are typically sketched to orient their non-reducing end in either the left or upward direction.
  3. Shape and color: Shapes and colors are completely consistent with stereochemistry only for hexoses, hexosamines, N-acetylhexosamines, hexuronates, and pentoses. Shapes only are consistent for deoxyhexoses, deoxy-N-acetylhexosamines, dideoxyhexoses, and nonulosonates.
  4. Ring configuration: A colored symbol encodes a defined monosaccharide (including D or L) independent of rotation or mirroring. Avoid rotations if possible.
    Pyranose form is assumed by default for all monosaccharides except Api. A few monosaccharides have absolute configurations implicitly specified in their name (D for Abe, Bac, Dha, Kdo, Mur, Par, Tyv; L for Col; DD for Kdn, Neu, Leg, 4eLeg; LL for Pse, Aci). For all other residues, absolute configuration is assumed by default: L for Ara, Fuc, Ido, IdoA, Rha, Alt, AltA, Sor, Api; and D for other monosaccharides.
    Less common configurations need to be stated in a figure legend or by adding the letters inside the symbol (e.g., adding D or L to the symbol). Epimers at C8 of nonulosonates can be indicated by adding "8D" or "8L" inside the symbol. Furanose rings can be indicated by adding an italicized "f" inside the symbol, and alditols can be indicated with an italicized "o" inside the symbol.
  5. Linkage presentation: Anomeric notation and destination linkage can be indicated in IUPAC style in figures, with or without a dash and with or without the originating carbon number (but with no commas or spacing) (e.g., Neu5Acα2-3Galβ1-4GlcNAc, Neu5Acα3Galβ4GlcNAc, or equivalents in symbol drawings)
    All monosaccharide glycosidic linkages are assumed to originate from C-1—except for 2-ketoses, which are assumed to be linked from C-2. Linkages also have the option to follow the Oxford System that embeds both the specificity and anomericity of the monosaccharide linkages. Dual linkages (e.g., an outgoing linkage from an aldose in open form) can be shown by double lines. Linkages involving carbon-carbon bond (e.g., in C-glycosides) can be shown in different color. An internal phosphodiester can be shown with -P- between the symbols for the linked monosaccharides, with linkage positions if preferred.
  6. Sialic acid: Specific symbols are provided for the core sialic acids Neu5Ac, Neu5Gc, and Kdn, with modifications to be indicated in diagrams (e.g., 9Ac for 9-O-acetylation). A red diamond can be used for any Sia (sialic acid, type unknown, whether Neu5Gc or Neu5Ac, or any of the other >50 forms known to date).
  7. Carbohydrate modifications: Abbreviations for modifications (e.g., sulfate or O-acetyl esters) follow the style of the Figure 1.5 of the Third Edition of Essentials, using attached letters, with numbers indicating linkage positions, if known (e.g., 9Ac for 9-O-acetyl group; 3S for 3-O-sulfate group; 6P for a 6-O-phosphate group; 8Me for 8-O-methyl group; 9Lt for 9-O-lactyl group; or 4,6Py for 4,6-pyruvyl group, etc.; abbreviations for multiple modifications can be concatenated). The presence of variable amounts of substituents can be indicated using +/- symbol or by indicating % presence if known, e.g. "60% 3Ac" to indicate presence of 3Ac on 60% of a residue or repeating unit.
  8. Amino substitution: For N-substituted groups it is assumed that there is only one amino group on the monosaccharide, with an already known common position (e.g., NS for N-sulfate group on glucosamine is assumed to be at the 2-position). For amino sugars in which the nitrogen is not at the most common carbon, add a number to the N (e.g., Rha4N is shown as a green triangle with 4N attached). Additionally, atypical acetamido groups may be represented using NAc (e.g. Fuc4NAc is shown using red triangle with 4NAc attached).
  9. Ambiguous assignments: White symbols based on the standard shapes designate monosaccharides with unknown/undefined stereochemistry (e.g., a white circle designates a hexose, type not defined, or a white diamond, any deoxynonulosonic acid). Other unknown or partially defined monosaccharides may be represented using a white flat hexagon.
  10. Structures not present in table and non-glycan assignments: Monosaccharides absent in Table 1 or modifications that cannot be represented using the above rules, may be indicated using a single non-italicized letter (A..Z) within an SNFG white symbol, with additional details provided in figure footnote or legends. The choice of white symbol to use should fit the generic type if possible: circle for hexose, triangle for deoxy hexose etc.; otherwise the white pentagon should be used. Any black shape can be used to depict non-monosaccharide structures and detailed definitions should be provided in figure legends. More complicated modifications of the SNFG are discouraged, and if these modifications are made should not be referred to as following the SNFG nomenclature.

Examples of Glycan Symbol Nomenclature

Glycan examples 1
Glycan examples 2


Table 2. CMYK and RGB color assignments

ColorCMYK settingsRGB settings
White0/0/0/0255/255/255
Blue100/50/0/00/144/188
Green100/0/100/00/166/81
Yellow0/15/100/0255/212/0
Light blue41/5/3/0143/204/233
Pink0/47/24/0246/158/161
Purple38/88/0/0165/67/153
Brown32/48/76/13161/122/77
Orange0/65/100/0244/121/32
Red0/100/100/0237/28/36
* CMYK colors are presented as %



Table 3. Monosaccharide abbreviations and names

AbbreviationShort NameSystematic name
4eLeg4-Epilegionaminic acid5,7-Diamino-3,5,7,9-tetradeoxy-D-glycero-D-talo-non-2-ulopyranosonic acid
6dAlt6-Deoxy-L-altrose6-Deoxy-L-altropyranose
6dAltNAcN-Acetyl-6-deoxy-L-altrosamine2-Acetamido-2,6-dideoxy-L-altropyranose
6dGul6-Deoxy-D-gulose6-Deoxy-D-gulopyranose
6dTal6-Deoxy-D-talose6-Deoxy-D-talopyranose
6dTalNAcN-Acetyl-6-deoxy-D-talosamine2-Acetamido-2,6-dideoxy-D-talopyranose
AbeAbequose3,6-Dideoxy-D-xylo-hexopyranose
AciAcinetaminic acid5,7-Diamino-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulopyranosonic acid
AllD-AlloseD-Allopyranose
AllAD-Alluronic acidD-Allopyranuronic acid
AllND-Allosamine2-Amino-2-deoxy-D-allopyranose
AllNAcN-Acetyl-D-allosamine2-Acetamido-2-deoxy-D-allopyranose
AltL-AltroseL-Altropyranose
AltAL-Altruronic acidL-Altropyranuronic acid
AltNL-Altrosamine2-Amino-2-deoxy-L-altropyranose
AltNAcN-Acetyl-L-altrosamine2-Acetamido-2-deoxy-L-altropyranose
ApiL-Apiose3-C-(Hydroxymethyl)-L-erythro-tetrofuranose
AraL-ArabinoseL-Arabinopyranose
BacBacillosamine2,4-Diamino-2,4,6-trideoxy-D-glucopyranose
ColColitose3,6-Dideoxy-L-xylo-hexopyranose
DDmanHepD-glycero-D-manno-HeptoseD-glycero-D-manno-Heptopyranose
Dha3-Deoxy-D-lyxo-heptulosaric acid3-Deoxy-D-lyxo-hept-2-ulopyranosaric acid
DigD-Digitoxose2,6-Dideoxy-D-ribo-hexopyranose
FruD-FructoseD-arabino-Hex-2-ulopyranose
FucL-Fucose6-Deoxy-L-galactopyranose
FucNAcN-Acetyl-L-fucosamine2-Acetamido-2,6-dideoxy-L-galactopyranose
GalD-GalactoseD-Galactopyranose
GalAD-Galacturonic acidD-Galactopyranuronic acid
GalND-Galactosamine2-Amino-2-deoxy-D-galactopyranose
GalNAcN-Acetyl-D-galactosamine2-Acetamido-2-deoxy-D-galactopyranose
GlcD-GlucoseD-Glucopyranose
GlcAD-Glucuronic acidD-Glucopyranuronic acid
GlcND-Glucosamine2-Amino-2-deoxy-D-glucopyranose
GlcNAcN-Acetyl-D-glucosamine2-Acetamido-2-deoxy-D-glucopyranose
GulD-GuloseD-Gulopyranose
GulAD-Guluronic acidD-Gulopyranuronic acid
GulND-Gulosamine2-Amino-2-deoxy-D-gulopyranose
GulNAcN-Acetyl-D-gulosamine2-Acetamido-2-deoxy-D-gulopyranose
IdoL-IdoseL-Idopyranose
IdoAL-Iduronic acidL-Idopyranuronic acid
IdoNL-Idosamine2-Amino-2-deoxy-L-idopyranose
IdoNAcN-Acetyl-L-idosamine2-Acetamido-2-deoxy-L-idopyranose
Kdn3-Deoxy-D-glycero-D-galacto-nonulosonic acid3-Deoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid
Kdo3-Deoxy-D-manno-octulosonic acid3-Deoxy-D-manno-oct-2-ulopyranosonic acid
LegLegionaminic acid5,7-Diamino-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid
LDmanHepL-glycero-D-manno-HeptoseL-glycero-D-manno-Heptopyranose
LyxD-LyxoseD-Lyxopyranose
ManD-MannoseD-Mannopyranose
ManAD-Mannuronic acidD-Mannopyranuronic acid
ManND-Mannosamine2-Amino-2-deoxy-D-mannopyranose
ManNAcN-Acetyl-D-mannosamine2-Acetamido-2-deoxy-D-mannopyranose
MurMuramic acid2-Amino-3-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucopyranose
MurNAcN-Acetylmuramic acid2-Acetamido-3-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucopyranose
MurNGcN-Glycolylmuramic acid3-O-[(R)-1-Carboxyethyl]-2-deoxy-2-glycolamido-D-glucopyranose
NeuNeuraminic acid5-Amino-3,5-dideoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid
Neu5AcN-Acetylneuraminic acid5-Acetamido-3,5-dideoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid
Neu5GcN-Glycolylneuraminic acid3,5-Dideoxy-5-glycolamido-D-glycero-D-galacto-non-2-ulopyranosonic acid
OliOlivose2,6-Dideoxy-D-arabino-hexopyranose
ParParatose3,6-Dideoxy-D-ribo-hexopyranose
PsePseudaminic acid5,7-Diamino-3,5,7,9-tetradeoxy-L-glycero-L-manno-non-2-ulopyranosonic acid
PsiD-PsicoseD-ribo-Hex-2-ulopyranose
QuiD-Quinovose6-Deoxy-D-glucopyranose
QuiNAcN-Acetyl-D-quinovosamine2-Acetamido-2,6-dideoxy-D-glucopyranose
RhaL-Rhamnose6-Deoxy-L-mannopyranose
RhaNAcN-Acetyl-L-rhamnosamine2-Acetamido-2,6-dideoxy-L-mannopyranose
RibD-RiboseD-Ribopyranose
SiaSialic acidSialic acid residue of unspecified type
SorL-SorboseL-xylo-Hex-2-ulopyranose
TagD-TagatoseD-lyxo-Hex-2-ulopyranose
TalD-TaloseD-Talopyranose
TalAD-Taluronic acidD-Talopyranuronic acid
TalND-Talosamine2-Amino-2-deoxy-D-talopyranose
TalNAcN-Acetyl-D-talosamine2-Acetamido-2-deoxy-D-talopyranose
TyvTyvelose3,6-Dideoxy-D-arabino-hexopyranose
XylD-XyloseD-Xylopyranose

Clicking on the abbreviation leads to the corresponding entry in PubChem

Updates

May 9, 2019

  1. Footnote 7 modified to accommodate variable modifications.
  2. More SNFG usage examples added.

January 22, 2019

  1. SNFG page reorganized with new examples from mammals, yeast, slime mold, insects, bacteria and plants.
  2. The new examples focus on how to present carbohydrate structures in diverse organisms and ambiguous monosaccharide assignments.
  3. Number of footnotes reduced from 28 to 10, and thematically organized in order to simplify usage.
  4. Single non-italicized letter is now allowed in white symbols to help describe monosaccharides that are not part of the SNFG table and that cannot be described using existing footnotes.
  5. SNFG Discussion Group list updated.

June 5, 2017

  1. SNFG Discussion Group Listing added.
  2. White diamond now indicates any deoxynonulosonic acid.
  3. Flattened diamond introduced for any dideoxynonulosonic acid.
  4. Additional symbols added for 6dGul, 6dAltNAc, 6dTalNAc, Pse, Leg, Aci and 4eLeg.
  5. Drawglycan-SNFG and Glycanbuilder 2-SNFG adopted, link to web site provided.
  6. Updates to Appendix 52A. Organizations and publications adopting SNFG.
  7. RGB color code provided in addition to CMYK
  8. Multiple minor corrections and additions to nomenclature and rules of display.

August 31, 2016

  1. Link to new Appendix 52A. Organizations and Publications Adopting SNFG.
  2. Red diamond introduced for Sia (sialic acid, type unspecified). White diamond indicates any nonulosonic acid.
  3. A 3D Symbol Nomenclature for Glycans (3D-SNFG) adopted, link to web site provided.
  4. Multiple minor corrections and additions to nomenclature and rules of display.

NCBI Glycans page