Difference between revisions of "Part:BBa K2918003"

Revision as of 11:26, 5 October 2019

Φ29 Double Stranded Binding Protein (DSB/p6)

Double Stranded Binding protein of the Φ29 bacteriophage

Sequence and Features

Overview

The replication of DNA and its conversion into functional proteins are vital processes in all living systems. DNA is copied during the replication process. The bacteriophage Φ29 contains a DNA replication machinery which replicates the linear plasmid by itself. This process is called orthogonal replication and can be beneficially used. The desired gene can be expressed in other hosts without interfering with the genome of its host. Our Sci-Phi 29 tool is based on the Φ29 DNA replication system and its four proteins. The terminal proteins (TP) cap the linear DNA, protect the linear DNA and are the starting point for the Φ29 DNA polymerase (DNAP/p2). DNAP binds to the TP and replicates the DNA. During the replication, single and double stranded DNA is protected by respectively single stranded DNA binding proteins (SSB/p5) and double stranded DNA binding proteins (DSB/p6).

Strain Construction

The DNA sequence of the part was synthesized by IDT with flanking BpiI sites and respective MoClo compatible coding sequence overhangs. The part was then cloned in a level 0 MoClo backbone (pICH41308) and the sequence was confirmed by sequencing. The cloning protocol can be found in the MoClo section below.

Modular Cloning

Modular Cloning (MoClo) is a system which allows for efficient one pot assembly of multiple DNA fragments. The MoClo system consists of Type IIS restriction enzymes that cleave DNA 4 to 8 base pairs away from the recognition sites. Cleavage outside of the recognition site allows for customization of the overhangs generated. The MoClo system is hierarchical. First, basic parts (promoters, UTRs, CDS and terminators) are assembled in level 0 plasmids in the kit. In a single reaction, the individual parts can be assembled into vectors containing transcriptional units (level 1). Furthermore, MoClo allows for directional assembly of multiple transcriptional units. Successful assembly of constructs using MoClo can be confirmed by visual readouts (blue/white or red/white screening). For the protocol, you can find it here.

Note: The basic parts sequences of the Sci-Phi 29 collection in the registry contain only the part sequence and therefore contain no overhangs or restriction sites. For synthesizing MoClo compatible parts, refer to table 2. The complete sequence of our parts including backbone can be found here.

Table 1: Overview of different level in MoClo

For synthesizing basic parts, the part of interest should be flanked by a BpiI site and its specific type overhang. These parts can then be cloned into the respective level 0 MoClo parts. For level 1, where individual transcriptional units are cloned, the overhangs come from the backbone you choose. The restriction sites for level 1 are BsaI. However, any type IIS restriction enzyme could be used.

Table 2: Type specific overhangs and backbones for MoClo. Green indicates the restriction enzyme recognition site. Blue indicates the specific overhangs for the basic parts