Difference between revisions of "Part:BBa K1666000"

Revision as of 14:46, 6 September 2015

LsrA of LuxS/AI-2 signaling pathway in Salmonalla

Quorum sensing is a process of bacterial cell-to-cell communication involving the production and detection of signaling molecules named autoinducers. And autoinducer-2 (AI-2) serves as a 'universal signal' for interspecies communication. In the LuxS/AI-2 signaling system of Salmonella Typhimurium, AI-2 response involves ATP binding cassette transporter encoded by genes named lsr (LuxS regulated). And LsrA is ATP-binding protein that provides energy for AI-2 transport.

Usage and Biology

AI-2 is generated by many species of Gram-negative and Gram-positive bacteria. In a group of bacteria exemplified by Salmonella, AI-2 response involves lsr genes that encode ATP binding cassette-type transporter. And LsrA is part of the ABC transporter complex, being responsible for energy coupling to the transport system.

Fig1. Schematic overview of the AI-2 response pathway in Salmonella TyphimuriumThe precursor of AI-2, 4,5-Dihydroxy-2,3-Pentanedione (DPD) , is a byproduct generated when LuxS converts S-Ribosylhomocysteine (SRH) to Homocysteine (HCY). DPD then undergoes spontaneously cyclization, forming AI-2, and exports to the culture supernatant. After that, extracellular AI-2 bounds to LsrB, following by passing the membrane channel and importing the cytoplasm. LsrK phosphorylates AI-2 afterwards. The lsr operon is repressed until phosphorylated AI-2 causes LsrR to relieve its repression on the promoter. And this allows further AI-2 import.

In our project, we set this protein-coding part under the regulation of a nisA promoter which can be activated by food-grade inducer, nisin. We linearized the related expression vectors and stably integrate them into the genome of the hosts. And together with other parts, we will construct a membrane channel for AI-2 generated by pathogens in the engineered bacteria.

Fig2. Part of the vector containing lsrA We use nisA promoter to initiate the transcription of lsrA gene

Sequence and Featuresexpre

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 AgeI site found at 939
1000
COMPATIBLE WITH RFC[1000]

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 ===Usage and Biology===
-AI-2 is generated by many species of Gram-negative and Gram-positive bacteria. In a group of bacteria exemplified by ''Salmonella'', AI-2 response involves ''lsr'' genes that encode ATP binding cassette-type transporter. And ''lsrA'' is part of the ABC transporter complex, being responsible for energy coupling to the transport system.
+AI-2 is generated by many species of Gram-negative and Gram-positive bacteria. In a group of bacteria exemplified by ''Salmonella'', AI-2 response involves ''lsr'' genes that encode ATP binding cassette-type transporter. And LsrA is part of the ABC transporter complex, being responsible for energy coupling to the transport system.
-[[File:NEFU_China_2015_AI-2_response_in_Salmonalla.png|550px|thumb|center|'''Fig1. Schematic overview of the AI-2 response pathway in ''Salmonella Typhimurium'''''The precursor of AI-2, 4,5-Dihydroxy-2,3-Pentanedione (DPD) , is a byproduct generated when LuxS converts S-Ribosylhomocysteine (SRH) to Homocysteine (HCY). DPD then undergoes spontaneously cyclization, forming AI-2, and exports to the culture supernatant. After that, extracellular AI-2 bounds to LsrB, following by passing the membrane channel and importing the cytoplasm. LsrK phosphorylates AI-2 afterwards. The lsr operon is repressed until phosphorylated AI-2 causes LsrR to relieve its repression on the promoter. And this allows further AI-2 import.]]
+[[File:NEFU_China_2015_AI-2_response_in_Salmonalla.png|550px|thumb|center|'''Fig1. Schematic overview of the AI-2 response pathway in ''Salmonella Typhimurium'''''The precursor of AI-2, 4,5-Dihydroxy-2,3-Pentanedione (DPD) , is a byproduct generated when LuxS converts S-Ribosylhomocysteine (SRH) to Homocysteine (HCY). DPD then undergoes spontaneously cyclization, forming AI-2, and exports to the culture supernatant. After that, extracellular AI-2 bounds to LsrB, following by passing the membrane channel and importing the cytoplasm. LsrK phosphorylates AI-2 afterwards. The ''lsr'' operon is repressed until phosphorylated AI-2 causes LsrR to relieve its repression on the promoter. And this allows further AI-2 import.]]
 In our project, we set this protein-coding part under the regulation of a nisA promoter which can be activated by food-grade inducer, nisin. We linearized the related expression vectors and stably integrate them into the genome of the hosts. And together with other parts, we will construct a membrane channel for AI-2 generated by pathogens in the engineered bacteria.