Takano M, Takahashi M, Oobatake M, Asada K
J Biochem. 1985 Nov;98(5):1333-40. doi: 10.1093/oxfordjournals.jbchem.a135400.
To reveal the molecular orientation of plastocyanin (PC) on spinach thylakoid membranes, the position of Lys residues modified by acetic anhydride was compared between thylakoid-bound PC and the isolated one. Digestion of the isolated PC by a trypsin yielded a peptide map with seven spots prior to the acetylation of the protein; none of the spots appeared after the isolated PC was acetylated. On the other hand, there were two spots on the peptide map of the PC acetylated when it was bound to the thylakoids. Those spots were revealed by their amino acid compositions to correspond to the peptide fragments Phe 82-Lys 95 and Val 96-Asn 99. Thus, the Lys residues 81 and 95 of the thylakoid-bound PC were not acetylated. These results suggest that the PC molecule binds to the thylakoids with a specific region including the Lys's 81 and 95 in contact with the membranes. The Lys's 81 and 95 are located near Tyr 83, which has been thought to be the delivery site of electrons from the Cu2+ center.
为了揭示质体蓝素（PC）在菠菜类囊体膜上的分子取向，比较了类囊体结合型PC和分离型PC中被乙酸酐修饰的赖氨酸残基的位置。在蛋白质乙酰化之前，用胰蛋白酶消化分离型PC得到了一个有七个斑点的肽图；分离型PC乙酰化后，这些斑点都没有出现。另一方面，与类囊体结合时乙酰化的PC的肽图上有两个斑点。通过氨基酸组成分析发现，这些斑点对应于肽片段Phe 82-Lys 95和Val 96-Asn 99。因此，类囊体结合型PC的赖氨酸残基81和95没有被乙酰化。这些结果表明，PC分子通过包括赖氨酸残基81和95的特定区域与类囊体结合，该区域与膜接触。赖氨酸残基81和95位于酪氨酸83附近，酪氨酸83被认为是来自Cu2+中心的电子传递位点。
