Complete amino acid sequence of poplar plastocyanin b

[摘要]

A second type of plastocyanin, plastocyanin b (PCb) was isolated from leaves of poplar Populus nigra var. Italica. The complete amino acid sequence of 99 residues in the single polypeptide chain of plastocyanin b has been determined: DVLLGADDG SLAFVPSEFS GEKIVFK NNAGFPHN FDEDPSGV DSKISMSEE DLLNAKGETF EVALSKGEY FYCSPHQGA GMVGKVVN The sequence obviously demonstrates, that PCb, in comparison with the known plastocyanin, plastocyanin a (PCa), has 12 amino acid replacements (underlined letters): Ile 1→Val, Ile 21-Ser 22-Pro 23→Val-Pro-Ala, Ile 39-Val 40→Val-Leu, Ser 45-Ile 46→ Ala-Val, Ala 52→Val, Asn 76→Asp, Ser 81→Thr and Thr 97→Ile. The replacements at positions 40 and 76 of PCb are probably essential for differences in its redox and electrochemical properties, respectively.

[学科分类] 生物化学/生物物理

[关键词] Primary structure;Plastocyanin b;Plastocyanin a;Molecular heterogeneity;(Populus nigra);T;tryptic peptides of PCb;ChT;chymotryptic peptides of PCb;CB;CNBr cleavage peptides of PCb