龙须菜及其色素突变体藻胆蛋白的光谱及分子特征的比较

对龙须菜(Gracilaria lemaneiformis Greville)及其色素突变体藻胆蛋白吸收光谱进行了比较研究,结果显示不同藻株藻红蛋白的吸收光谱有显著的变化,而藻蓝蛋白和别藻蓝蛋白的基本相同.我们克隆了龙须菜及其色素突变体的藻红蛋白亚基的部分基因序列,用该基因序列推导出的氨基酸序列进行分析以揭示这一变化的分子机理,结果显示除几个氨基酸残基的替换外,几株藻间的藻红蛋白的氨基酸序列十分相似,一些氨基酸的替换发生在决定藻红蛋白二级结构及亚基间相互作用的区域,可能会影响藻胆蛋白的构型及相互作用,导致光谱性质的变化.

Comparison of Phycobiliproteins from Gracilaria lemaneiformis (Rhodophyceae) and Its Pigment Mutants in Spectral and Molecular Respects

Comparative studies of absorption spectra of phycobiliproteins of Gracilaria lemaneiformis Greville and its pigmental mutants were conducted in this study. The results showed that the absorption spectra of phycoerythrins (PE) from different material changed significantly, while those of phycocyanins(PC)and allophycocyanins (APC) were basically similar. In order to disclose the essence of the difference, partial sequences of the subunit genes of PE of Qingdao strain of G. lemaneiformis (qd) and its pigmental mutants were determined. The amino acid sequences were deduced and used to explain spectral shifts of PE from the pigmental mutants. The amino acid sequences of PE resembled each other, and several residues changed among qd and its pigmental mutants. Residue substitutions were found in a region consisting of amino acids which determined the secondary structure and subunits interactions, thus might influence the confirmation and interaction of subunits, and further caused spectral deviation.