167980 20260128112902.0 doi 10.1016/j.abb.2007.08.024 sideral 64703 ART-2007-64703 eng Frago, Susana Universidad de Zaragoza Tuning of the FMN Binding and Oxido-Reduction Properties by Neighboring Side Chains in Anabaena Flavodoxin 2007 Access copy available to the general public Unrestricted Contribution of three regions (phosphate-binding, 50’s and 90’s loops) of Anabaena apoflavodoxin to FMN binding and reduction potential was studied. Thr12 and Glu16 did not influence FMN redox properties, but Thr12 played a role in FMN binding. Replacement of Trp57 with Glu, Lys or Arg moderately shifted Eox/sq and Esq/hq and altered the energetic of the FMN redox states binding profile. Our data indicate that the side chain of position 57 does not modulate Eox/sq by aromatic stacking or solvent exclusion, but rather by influencing the relative strength of the H-bond between the N(5) of the flavin and the Asn58-Ile59 bond. A correlation was observed between the isoalloxazine increase in solvent accessibility and less negative Esq/hq. Moreover, Esq/hq became less negative as positively charged residues were added near to the isoalloxazine. Ile59 and Ile92 were simultaneously mutated to Ala or Glu. These mutations impaired FMN binding, while shifting Esq/hq to less negative values and Eox/sq to more negative. These effects are discussed on the bases of the X-ray structures of some of the Fld mutants, suggesting that in Anabaena Fld the structural control of both electron transfer steps is much more subtle than in other Flds. info:eu-repo/semantics/openAccess by-nc-nd https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es 2.578 2007 BIOPHYSICS 32 / 67 = 0.478 2007 Q2 T2 BIOCHEMISTRY & MOLECULAR BIOLOGY 131 / 262 = 0.5 2007 Q2 T2 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Goñi, Guillermina Universidad de Zaragoza (orcid)0000-0003-4010-849X Herguedas, Beatriz (orcid)0000-0003-2044-4795 Peregrina, Jose Ramon Serrano , Ana Universidad de Zaragoza Perez-Dorado, Inmaculada Molina, Rafael Gomez-Moreno, Carlos Hermoso, Juan A. Martinez-Julvez, Marta Universidad de Zaragoza (orcid)0000-0001-9047-0046 Mayhew, Stephen G. Medina, Milagros Universidad de Zaragoza (orcid)0000-0001-8743-0182 1002 060 Universidad de Zaragoza Dpto. Bioq.Biolog.Mol. Celular Área Bioquímica y Biolog.Mole. 467, 2 (2007), 206-217 Arch. biochem. biophys. ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 0003-9861 520769 http://zaguan.unizar.es/record/167980/files/texto_completo.pdf Postprint 1021417 http://zaguan.unizar.es/record/167980/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:167980 articulos driver 2026-01-28-11:24:55 ARTICLE