FMN is covalently attached to a threonine residue in the NqrB and NqrC subunits of Na+‐translocating NADH‐quinone reductase from Vibrio alginolyticus

FEBS Letters

Furuishi, Kazuchika²  Nakayama, Yuji¹  Hayashi, Maki¹  Unemoto, Tsutomu¹  Yasui, Mikako¹  Maeda, Masahiro² 

[1] Laboratory of Membrane Biochemistry, Faculty of Pharmaceutical Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan;Applied Biosystems Japan, 4-5-4 Hatchobori, Chuo-ku, Tokyo 104-0032, Japan

关键词: Covalently bound flavin;    FMN;    Na+-translocating NADH-quinone reductase;    Threonine;    Matrix-assisted laser desorption ionization time-of-flight mass spectrometry;    Vibrio alginolyticus;   

DOI  :  10.1016/S0014-5793(00)02404-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The Na⁺-translocating NADH-quinone reductase (NQR) from Vibrio alginolyticus is composed of six subunits (NqrA to NqrF). We previously demonstrated that both NqrB and NqrC subunits contain a flavin cofactor covalently attached to a threonine residue. Fluorescent peptide fragments derived from the NqrB and NqrC subunits were applied to a matrix-assisted laser desorption ionization time-of-flight mass spectrometer, and covalently attached flavin was identified as FMN in both subunits. From post-source decay fragmentation analysis, it was concluded that FMN is attached by a phosphate group to Thr-235 in the NqrB subunit and to Thr-223 in the NqrC subunit. The phosphoester binding of FMN to a threonine residue reported here is a new type of flavin attachment to a polypeptide.

【 授权许可】

Unknown