藍藻蛋白為存在於大部分藍綠藻菌中非核醣體合成的聚合物，由1887年Borzi在顯微鏡底下觀察後發現；藍藻蛋白的合成需有藍藻蛋白合成酶才能進行聚合，由等比例的Asp與Arg所組成，屬於生物體自身合成的聚胺基酸，可作為生物體碳源及氮源。
　　本研究以Synechocystis sp. PCC 6803 cphA 之E. coli BL21- CodonPlus(DE3)-RIL進行探討，質體系統為pET系統，在經過IPTG誘導以及外加不同濃度的Arg、Lys、Glu以及Asp之後，經由純化步驟而得到藍藻蛋白。進一步比較藍藻蛋白產率、分子量，且利用高效液相層析儀分析胺基酸組成。亦將藍藻蛋白進行MALDI-TOF MS、XRD、熱重分析、傅立葉轉換紅外光譜分析。
　　實驗結果顯示於培養基中外加Glu和Asp培養菌體並不會對於藍藻蛋白產率及胺基酸組成有所影響。培養基中外加Arg可生產較多的非水溶性藍藻蛋白，並降低了水溶性藍藻蛋白的生成，且於蛋白質電泳上觀察到藍藻蛋白分子量降低，非水溶性部分為17.4 ~ 34.8 kDa，水溶性部分為8.3 ~ 20.3 kDa，且以胺基酸分析水溶性藍藻蛋白Arg比例為36.46 ± 0.49 %，較控制組Arg比例22.38 ± 0.63 % 高，以MALDI-TOF MS分析其水溶性藍藻蛋白平均分子量18.84 kDa較控制組的平均分子量20.19 kDa來的低，XRD分析結果指出外加Arg培養會使水溶性藍藻蛋白結晶度降低；外加Lys培養可生產較多的水溶性藍藻蛋白，並降低了非水溶性藍藻蛋白的生成，對於藍藻蛋白的分子量以及胺基酸組成並沒有太大的改變。最後以熱重分析與傅立葉轉換紅外光譜分析藍藻蛋白，發現到外加胺基酸培養與否和藍藻蛋白裂解溫度及官能基吸收值皆沒有太大關聯。
　　總結以上，外加Arg進行培養對於藍藻蛋白的分子量、非水溶性藍藻蛋白比例、胺基酸組成皆有影響，外加Lys有助於提高水溶性藍藻蛋白的產率。

Cyanophycin granule polypeptide (CGP) is a non-ribosomal protein found in most groups of cyanobacteria. It was discovered in 1887 by Borzi during microscopic studies of cyanobacteria. Most cyanobacteria harbor a functional cyanophycin synthetase gene (cphA) and synthesize CGP. The branched polymer consists of an equimolar amount of arginine and aspartic acid.
In this study, we used Synechocystis sp. PCC 6803 cphA in E. coli BL21-CodonPlus(DE3)-RIL to produce CGP. The pET expression system was employed to produce CGP. After induction by 0.01 mM IPTG and different amounts of supplemented amino acids to the culture medium, the yields of purified CGP were compared. The molecular weights were analyzed by SDS-PAGE and MALDI-TOF MS. The amino acid compositions were assayed by HPLC. The physical properties of CGP were further analyzed by XRD, TGA, and FTIR.
The results showed that the medium supplemented with either glutamate or aspartic acid had no effect on the amino acid compositions of CGP. The bacteria grown in the presence of arginine produced a higher amount of insoluble CGP contents with a reduced yield of soluble CGP contents. The molecular weights of both insoluble (17.4-34.8 kDa) and soluble (8.3-20.3 kDa) CGP analyzed by SDS-PAGE were lower than the CGP from the non-supplemented culture condition. The purified soluble CGP from the supplemented arginine culture showed 36.46±0.49 mole% arginine, higher than the purified soluble CGP (22.38±0.63 mole% arginine) from the unsupplemented culture condition. The molecular weight of arginine-rich soluble CGP analyzed by MALDI-TOF MS is 18.84 kDa, lower than the typical soluble CGP (20.19 kDa). In addition, the medium supplemented with arginine might decrease the crystallinity of soluble CGP. The medium supplemented with lysine showed a higher soluble CGP content with a decreased insoluble CGP content, and had no effect on the amino acid compositions of CGP. The TGA and FTIR analysis showed that the CGP exhibited similar properties irrespective of the supplemented amino acids.
In conclusion, the bacteria grown in the presence of supplemented arginine may affect the molecular weight, yield, and amino acid compositions of CGP. The supplementation of the medium with lysine could increase the soluble CGP yield.

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