Part:BBa_K200003

Rfal
Waal ligase is an enzyme responsible for the ligation of an O-antigen to the core oligosaccharide in the Gram-negative bacterium's outer membrane.

Unlike other exopolysaccharides, colanic acid does not naturally bind to the cell surface but rather forms a thick mesh between cells. While Waal Ligase usually links the O-antigen to the core oligosaccharide, in K-12 it links colanic acid to the core oligosaccharide. This is because E.coli K-12 does not produce O-antigen due to an insertion mutation.

Usage and Biology

Figure 1: LPS structure (source: [http://en.wikipedia.org/wiki/O_antigen wikipedia])

LipoPolySaccharyde is a major component of the outer cell wall in Gram-negative bacteria. It is constituted of three main components: the O-antigen, the core polysaccharides and the lipid A (see Fig. 1).
The O-antigen is a highly variable chain of polysaccharydes and is physically linked to the core.
The core component is made up of a short chain of sugars (oligosaccharide) and is linked to both the O-antigen and the Lipid A components of the cell wall.
The Lipid A component of the LPS contains fatty acid chains which causes the LPS to dock into the outer membrane of the Gram-negative bacterium.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 754
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

Requirements

• Gram-negative bacterium
• Colanic acid producing gene (rcsB)

References

<biblio>

1. function pmid=15838026
2. Function2 pmid=19019161

</biblio>