Tuning of the FMN binding and oxido-reduction properties by neighboring side chains in Anabaena flavodoxin
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Tuning of the FMN binding and oxido-reduction properties by neighboring side chains in Anabaena flavodoxin. / Frago, Susana; Goñi, Guillermina; Herguedas, Beatriz; Peregrina, José Ramón; Serrano, Ana; Perez-Dorado, Inmaculada; Molina, Rafael; Gómez-Moreno, Carlos; Hermoso, Juan A; Martínez-Júlvez, Marta; Mayhew, Stephen G; Medina, Milagros.
In: Archives of Biochemistry and Biophysics, Vol. 467, No. 2, 2007, p. 206-217.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Tuning of the FMN binding and oxido-reduction properties by neighboring side chains in Anabaena flavodoxin
AU - Frago, Susana
AU - Goñi, Guillermina
AU - Herguedas, Beatriz
AU - Peregrina, José Ramón
AU - Serrano, Ana
AU - Perez-Dorado, Inmaculada
AU - Molina, Rafael
AU - Gómez-Moreno, Carlos
AU - Hermoso, Juan A
AU - Martínez-Júlvez, Marta
AU - Mayhew, Stephen G
AU - Medina, Milagros
PY - 2007
Y1 - 2007
N2 - 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 E(ox/sq) and E(sq/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 E(ox/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 E(sq/hq). Moreover, E(sq/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 E(sq/hq) to less negative values and E(ox/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.
AB - 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 E(ox/sq) and E(sq/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 E(ox/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 E(sq/hq). Moreover, E(sq/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 E(sq/hq) to less negative values and E(ox/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.
KW - Anabaena/metabolism
KW - Binding Sites
KW - Enzyme Activation
KW - Flavin Mononucleotide/chemistry
KW - Flavodoxin/chemistry
KW - Kinetics
KW - Models, Chemical
KW - Models, Molecular
KW - Oxidation-Reduction
KW - Protein Binding
KW - Protein Structure, Tertiary
U2 - 10.1016/j.abb.2007.08.024
DO - 10.1016/j.abb.2007.08.024
M3 - Journal article
C2 - 17904516
VL - 467
SP - 206
EP - 217
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
SN - 0003-9861
IS - 2
ER -
ID: 203019764