Part:BBa_K3504007

Gly-Ala repeats

Part Description

Glycine-Alanine repeat (GAr) sequence of the Epstein-Barr virus-encoded EBNA-1 prevents presentation of antigenic peptides to major histocompatibility complex class I molecules. This has been attributed to its capacity to suppress mRNA translation in cis.

Usage

EBNA1 glycine-alanine repeat (GAR) domain when inserted in cis with CTL epitope can inhibit antigen presentation through preventing cytotoxic T-lymphocyte-epitope generation. GAR appears to inhibit the proteosomal degradation of indicator proteins into which the gly-ala repeat is introduced, therefore evades the recognition by CTLs. previous findings show that the Gly-Ala repeat prevents presentation of MHC class I-restricted epitopes through the inhibiting the ubiquitin/proteasome pathway.

Characterization

We have made simulations using mathematical modelling techniques which showed lower levels of CTLs degredation when adding the glycine-alanine repeats to our circuit compared to its degredation ratio without the repeats.

Figure 1. CTLs degredation ratio between it with the inhibitory effect of Gly-Ala repeat on CTLs attack on the left compared to traditionally without it on the right.

Improvements

This part was improved by changes in its sequence that allowed it to further protect the circuit.

Figure 1. Optimized Gly-Ala repeats.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 40
  Illegal NgoMIV site found at 64
  Illegal NgoMIV site found at 262
  Illegal NgoMIV site found at 403
  Illegal NgoMIV site found at 442
  Illegal NgoMIV site found at 505
  Illegal NgoMIV site found at 571
  
• 1000
  COMPATIBLE WITH RFC[1000]