Difference between revisions of "Part:BBa K200003"

Revision as of 09:39, 29 September 2009

Rfal
Rfal (Waal ligase) is an enzyme responsible for the ligation of an [http://en.wikipedia.org/wiki/O_antigen#O-antigen O-antigen] to the core [http://en.wikipedia.org/wiki/Oligosaccharide oligosaccharide] in the [http://en.wikipedia.org/wiki/Gram-negative_bacteria 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.
In the majority of E.coli, the enzyme Rfal joins the O-antigen to the membrane-bound lipid core molecule. Since the K-12 strain has an insertion mutation in the gene coding for O-antigen, the enzyme Rfal is free to join colanic acid to the lipid core.

The gene was used alongside RcsB and YgiV as part of the Imperial iGEM 2009 [http://2009.igem.org/Team:Imperial_College_London The E.ncapsulator] project to bind the colanic acid capsule to the cellular membrane.

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

function pmid=15838026
Function2 pmid=19019161
Function3 pmid=15215252

</biblio>

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 __NOTOC__
 <partinfo>BBa_K200003 short</partinfo><br>
-Rfal (Waal ligase) is an enzyme responsible for the ligation of an O-antigen to the core [http://en.wikipedia.org/wiki/Oligosaccharide oligosaccharide] in the Gram-negative bacterium's outer membrane.
+Rfal (Waal ligase) is an enzyme responsible for the ligation of an [http://en.wikipedia.org/wiki/O_antigen#O-antigen O-antigen] to the core [http://en.wikipedia.org/wiki/Oligosaccharide oligosaccharide] in the [http://en.wikipedia.org/wiki/Gram-negative_bacteria 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.