Crystal Structure of Dimeric Flavodoxin from Desulfovibrio gigas Suggests a Potential Binding Region for the Electron-Transferring Partner

International Journal of Molecular Sciences

Yin-Cheng Hsieh²  Tze Shyang Chia¹  Hoong-Kun Fun¹ 

[1] X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia; E-Mails:;Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan; E-Mail:

关键词: flavodoxin (Fld);    flavin mononucleotide (FMN);    crystal structure;    dimer;    binding region;   

DOI  :  10.3390/ijms14011667

来源: mdpi

【 摘 要 】

Flavodoxins, which exist widely in microorganisms, have been found in various pathways with multiple physiological functions. The flavodoxin (Fld) containing the cofactor flavin mononucleotide (FMN) from sulfur-reducing bacteria Desulfovibrio gigas (D. gigas) is a short-chain enzyme that comprises 146 residues with a molecular mass of 15 kDa and plays important roles in the electron-transfer chain. To investigate its structure, we purified this Fld directly from anaerobically grown D. gigas cells. The crystal structure of Fld, determined at resolution 1.3 Å, is a dimer with two FMN packing in an orientation head to head at a distance of 17 Å, which generates a long and connected negatively charged region. Two loops, Thr59–Asp63 and Asp95–Tyr100, are located in the negatively charged region and between two FMN, and are structurally dynamic. An analysis of each monomer shows that the structure of Fld is in a semiquinone state; the positions of FMN and the surrounding residues in the active site deviate. The crystal structure of Fld from D. gigas agrees with a dimeric form in the solution state. The dimerization area, dynamic characteristics and structure variations between monomers enable us to identify a possible binding area for its functional partners.

【 授权许可】

CC BY   
© 2013 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.