Difference between revisions of "Part:BBa K2762011"

Revision as of 13:59, 12 October 2018

PT7-B0034-rbcL-B0015-PT7-B0034-rbcX-B0034-rbcS-B0015

Background

Ribulose-1,5-biphosphate carboxylase/oxygenase catalyzes the first reaction of the Calvin cycle, converting the combination of Ribulose-1,5-biphosphate(RuBP) and carbon dioxide and then form two 3-phosphoglycerate molecular. 3-phophoglycerate will then convert to pyruvate by the native metabolic system of E coli. Previous studies have utilized E. coli as a host of studying point mutation and random mutation of RubisCO in order to enhance its enzyme activity. This study proved that installing rubisco gene into E. coli system is actually feasibly. After mining information from journal, we selected rubisco gene form Synechococcus elongtus PCC. 7002, which is a well-studied cyanobacteria.

Structure and the Function of the proein

The structure of RubisCO involves two polypeptide subunit: RbcL and RbcS. Each RubisCO is consist of eight RbcL and RbcS. RbcL, the large chain of RubisCO, contains the main active site. The active site requires Mg2+ ion. The ion binds to the certain amino acid of the centrol of RbcL, activate the RubisCo. Since the M9 medium contains Mg2+ ion, we only need to add little amount of additional ion, adjusting the concentration to 20mM.

It has reported that rbcL can be functional solely. However, researches have revealed that RbcS contribute to the activity and the CO2/O2 specification through the mutagenesis and hybridization of cyanobacteria RubisCo, and indicated the RbcS should take into consideration while constructing the Calvin cycle. For this reason, we decide to add RbcS gene to our construction.

RbcX, the subunit which doesn’t involve in the structure of RubisCO, however, plays an important role in the structure folding. Researches have revealed that without the presence of the RbcX chaperon, RubisCO cannot folding correctly. According to these researches, we take the RbcX into our consideration and add the gene into our construction.

Experiments

We did three experiments to confirm the expression and function of this part. First, we inserted the part on pSB1C3 and cloned the plasmid into DH5 alpha. We extracted the plasmid after the colony formed and did the enzyme digestion to confirm the insertion was successful. Second, we did the SDS-PAGE to confirm the presence of each polypeptide. Third, we cultured the BL21(DE3) with the T7-RubisCo part and PRK part in the M9-xylose medium in 5% CO2 incubator and normal incubator after inducing the RubisCo gene with IPTG. We also did the non-induced control groups. The result showed that the with the presence of these two functional enzymes. The E. coli grew faster and consumed more xylose in the CO2 rich environment.

Sequence and Features