Team:Harvard/Model
Pathway Model
1 Overview
Curli is the main proteinaceous component of the extracellular matrix naturally produced by *E. coli*. Although the main structural component is the self-assembling csgA monomer, there are a number of other proteins involved in its production and export. The curli production pathway can be broken down into two main modules: gene expression and translocation. The first, gene expression, is comprised of transcription and translation. Translocation can be further broken down into periplasmic export and extracellular secretion.
2 Gene Expression
2.1 Transcription
The naturally occurring genes corresponding to curli are organized into csgBAC and csgDEFG operons. csgD is a regulatory protein, and thus is not applicable for the expression of foreign plasmids. Additionally, due to the additional protein domains fused to the csgA monomer, it is placed on a plasmid on its own (gcsgA). The remaining genes are placed on another plasmid (gcsgCEFG). The rate of transcription is mainly governed by the plasmid copy number and promoter strength. gcsgA + RNApol → gcsgA + RNApol + mRNAcsgA $$g_{csgA}$$ $\alpha$ \[(Arab:AraC)\overset{K}{\rightarrow}mRNA\overset{\alpha}{\rightarrow}P\]
