Team:NYMU-Taipei/Project/Attachment

Revision as of 15:39, 1 August 2008 by Blent (Talk | contribs)

Motivation

E. coli is a bacterium that commonly lives in the intestines of people and animals.

When genetic E.coli sense the alternation of pH in intestine, adhesion mechanism will be turn on in order to enhance the ability of attachment.
Enhanced adhesion will make a chance for genetic E.coli to have more time to do events that we design in "Clearance of urea (phosphat, guanidine)" group.
To cooperate with "Time Regulation" group, we expect genetic E.coli to detach from intestinal epithelia cells at indicated time.

We have two strategies to enhance attachment in intestine: Expression of membrance form of FimH and FliC.

We will use the biobrick part!
- - BBa_J04500. a composite part of a lac promoter (R0010) and a strong ribosome binding site (B0034)[1]
  - BBa_J36835. Lpp, the lipoprotein signal peptide.[2]
  - BBa_J36837 or BBa_J36838. OmpA, one (O1) or five (O5) transmembrane domains, respectively. Both have been shown to work (Earhart, 2000).[3][4]
  - BBa_J36841 or BBa_J36843. Streptavidin, either wild-type "SW" (Howarth, 2006), or single-chain dimeric "SD" (Aslan, 2005).[5][6]

The FimH protein is the receptor recognizing element of type 1 fimbriae
Fimbriae
- Function: attachment of bacteria to its host as in case of pathogenic bacteria salmonella typhimurium , Nisseria gonorrhoea , bordella pertussis
- Size and number: Found much in number (up to 1000 per cell) having 3 to 25 nm in diameter and 0.5 to 20 micrometer in length.
Type 1 fimbriae are surface organelles of Escherichia coli which mediate D-mannose-sensitive binding to different host surfaces.
A single type 1 fimbria is a 7-nm-wide and »1-mm-long surface polymer, The bulk of the structure is made up of »1000 copies of the major subunit protein, FimA, polymerized into a right-handed helical structure.
Small quantities of the minor components (FimF, FimG, and FimH) are also present.
The FimH protein is the receptor recognizing element of type 1 fimbriae.
Studies on Salmonella Typhimurium revealed that FimH adhesin is responsible for bacteria binding to HeLa, HEp-2 and mouse intestinal epithelial cells.

Functional characterization of the FimH adhesin from Salmonella enterica serovar Enteritidis[7]
Combining sites of bacterial fimbriae [8]
Probing the receptor recognition site of the FimH adhesin by fimbriae- displayed FimH-FocH hybrids[9]
Host Protein Binding and Adhesive Properties of H6 and H7 Flagella of Attaching and Effacing Escherichia coli[10]
Sequence Diversity of the Escherichia coli H7 fliC Genes:Implication for a DNA-Based Typing Scheme forE. coli O157:H7[11]