PGLang

To represent complex, branched peptidoglycan structures using text, PGLang was developed. Both the Mass Calculator and Fragmenter modules of the WebUI take PGLang as an input. Below, you can see a number of cartoon muropeptide structures and their PGLang representations. Note that, when representing multimers, the donor must always come first!

A set of example structures and their PGLang representations

Syntax

A more complete description of the syntax can be seen in the railroad diagram below:

A railroad diagram describing PGLang's syntax

A more interactive and detailed version of the above can be found here.

Residues

The following residues are built into the PGLang provided via the WebUI and can be referred to by their abbreviations:

Symbol Name Formula Monoisotopic Mass
g N-Acetylglucosamine C8H15NO6 221.089937
m N-Acetylmuramic Acid C11H19NO8 293.111066
x Unknown Monosaccharide 0
A Alanine C3H7NO2 89.047678
B Diaminobutyric Acid C4H10N2O2 118.074227
C Cysteine C3H7NO2S 121.019749
D Aspartic Acid C4H7NO4 133.037507
E Glutamic Acid C5H9NO4 147.053157
F Phenylalanine C9H11NO2 165.078978
G Glycine C2H5NO2 75.032028
H Histidine C6H9N3O2 155.069476
I Isoleucine C6H13NO2 131.094628
J Diaminopimelic Acid C7H14N2O4 190.095356
K Lysine C6H14N2O2 146.105527
L Leucine C6H13NO2 131.094628
M Methionine C5H11NO2S 149.051049
N Asparagine C4H8N2O3 132.053492
O Ornithine C5H12N2O2 132.089877
P Proline C5H9NO2 115.063328
Q Glutamine C5H10N2O3 146.069142
R Arginine C6H14N4O2 174.111675
S Serine C3H7NO3 105.042593
T Threonine C4H9NO3 119.058243
U Homoserine C4H9NO3 119.058243
V Valine C5H11NO2 117.078978
W Tryptophan C11H12N2O2 204.089877
X Unknown Amino Acid 0
Y Tyrosine C9H11NO3 181.073893
Z Threo-3-Hydroxyglutamic Acid C5H9NO5 163.048072

Modifications

The following modifications are built into the PGLang provided via the WebUI and can be referred to by their abbreviations:

Symbol Name Lost Atoms Gained Atoms Net Monoisotopic Mass Targeted Functional Groups
Ac O-Acetylation H C2H3O 42.010564 "Hydroxyl" at="6-Position"
Am Amidation OH NH2 -0.984015 "Carboxyl" at="Sidechain"
Anh 1,6-Anhydro H2O -18.010564 "Hydroxyl" at="Reducing End" of="N-Acetylmuramic Acid"
DeAc De-N-Acetylation C2H3O H -42.010564 "Acetyl" at="Secondary Amide"
Glyc Glycolylation CH3 CH2OH 15.994914 "Acetyl" at="Secondary Amide" of="N-Acetylmuramic Acid"
Poly Wall Polymer Linkage H PO3 77.95068 "Hydroxyl" at="6-Position"
Red Reduced H2 2.01565 "Hydroxyl" at="Reducing End"

The “Targeted Functional Groups” column describes which residues these modifications can be legally attached to.