Michelle Kuttel


Installing and Running CarbBuilder


CarbBuilder is a program for building a reasonable structure of a polysaccharide from a primary structure specification in the CASPER format.

CarbBuilder is implemented in C# and should be portable across a variety of architectures with support for the .NET framework.

If you use CarbBuilder in your research, please cite these references:

  1. CarbBuilder: Software for Building Molecular Models of Complex Oligo- and Polysaccharide Structures. M. M. Kuttel, Jonas Stahle, and Goran Widmalm, J. Comput. Chem., 37(22), 2098-2105 (2016)
  2. - M. M. Kuttel et al., Proceedings of the 7th IEEE International Conference on e-Science, 2011, p 395-402 ==============================================


CarbBuiler is installed by downloading and expanding the archive, which contains:
+ CarbBuilder2.exe [the application file]
+ README.md [the README file]
+ structureFile directory [a directory containing structures for building and default settings]

On Linux or MacOS X you need to install Mono, an open source implementation of Microsoft's .NET Framework. Mono is free for download at http://www.mono-project.com/download/.


CarbBuilder is a command-line program: you need to open a terminal to execute it.

Examples of how to run CarbBuilder:

On Windows:

CarbBuilder2.exe -i "->2)aLRha(1->2)aLRha(1->3)aLRha(1->3)bDGlcNAc(1->" -r 6 -o Shigella_Y_RU6

On Linux [Note that running under Linux requires installation of the mono framework] :

mono CarbBuilder2.exe -i "->2)aLRha(1->2)aLRha(1->3)aLRha(1->3)bDGlcNAc(1->" -r 6 -o Shigella_Y_RU6

On MacOS [Note that running under MacOS requires installation of the mono framework]:

mono CarbBuilder2.exe -i "->2)aLRha(1->2)aLRha(1->3)aLRha(1->3)bDGlcNAc(1->" -r 6 -o Shigella_Y_RU6



  1. CarbBuilder2.exe -i "->4)aDGlc(1->" -r 20 -o starch
  2. This will build 20 repeats of a linear homopolysaccharide output in the starch.pdb file.

  3. CarbBuilder2.exe -i "aDMan(1->4)[aDGal(1->6)]aDGlc" -o trisacc
  4. This will build a branched trisaccharide.

  5. CarbBuilder2.exe -i "aDGlc3Ac" -o aDGlc3OAc
  6. This will build a glucose monsaccharide with 3 O-acetylation.

  7. CarbBuilder2.exe -i "->3)bDRibf(1->1)Ribol5P(O->" -r 6 -o Hib_6RU
  8. This will build 6-repeat units of the Haemophilus influenzae capcular polysaccharide, and illustrates both the linear ribotol residue as well as how to specify a phosphate linkage.

  9. CarbBuilder2.exe -i "->6)[aDNeu5Ac(2->3)bDGal(1->4)]bDGlcNAc(1->3)bDGal(1->4)bDGlc(1->" -r 6 -o strepBIII
  10. This will build 6-repeat units of Group B Streptococcus serotype III polysaccharide. This example illustrates branching in a heterpolysaccharide, as well as how to specify linkage from the 2-position in sialic acid (aDNeu5Ac). Note that side chains are in square brackets in the CASPER format - [aDNeu5Ac(2->3)bDGal(1->4)] - and are always listed immediated before the branching residue.

CASPER format for structure representation in CarbBuilder

In the CASPER format, monosaccharide residues (e.g. aDGlc, bLGalf, bLRha6Ac, aDManNAc) are represented by (in order):

Linkages are described within round brackets, uning "->" to indicate the direction. For examople, aDGal(1->4)aDGlcOMe; aDNeuNAc(2->6)aDGal etc.

Side chains are represented within square brackets placed immediately before the branching residue

Repeating units are represented by "open" linkages at either end:
or, with a branch,:

Some example structures:
A heptasaccharide:
O128 O-antigen PS:

Shigella flexneri X:

Methyl beta-cellobioside:

Xylose containing N glycan:

Repeating unit of E. coli O128 O-antigen:

Repeating unit of E. coli O105 O-antigen: