tailieunhanh - Báo cáo Y học: Probing the role of glutamic acid 139 of Anabaena ferredoxin-NADP+ reductase in the interaction with substrates

The role of the negative charge of the E139 side-chain of AnabaenaFerredoxin-NADP + reductase (FNR) in steering appropriate docking with its substrates ferredoxin, flavo-doxin and NADP + /H, that leads to efficient electron transfer (ET) is analysed by characterization of several E139 FNRmutants. Replacement of E139 affects the interaction with the different FNRsubstrates in very different ways. | Eur. J. Biochem. 269 4938-4947 2002 FEBS 2002 doi Probing the role of glutamic acid 139 of Anabaena ferredoxin-NADP reductase in the interaction with substrates Merche Faro1. Susana Frago1. Tomas Mavoral2 Juan A Hermoso2. Julia Sanz-Anaricio2 B B B B 4 B BB BB B B BB B B BB BB BB B BB B B B BB B B B BB V BB B BB B IV w BB B B B B B B B B B BB BV BB IV w B B BV B B BV B B B IBB BB B B VBB BB Carlos Gomez-Moreno1 and Milagros Medina1 1Departamento de Bioquimica y Biologia Molecular y Celular Facultad de Ciencias Universidad de Zaragoza Spain 2Grupo de Cristalografia Macromolecular y Biologia Estructural Instituto Quimica-Fisica Rocasolano . Serrano 119 Madrid Spain The role of the negative charge of the E139 side-chain of Anabaena Feteedoxin-NADP reductase FNR in steering appropriate docking with its substrates ferredoxin flavo-doxin and NADP H that leads to efficient electron transfer ET is analysed by characterization of several E139 FNR mu am Is. Repkieemenl of El 99 affectt the inlemclinn with the different FNR subttraees in eery different wyy. Thus while E139 does not appear to be involved in the processes of binding and ET between FNR and NADP H the nature and the conforeation of the residue at position 139 of Anaibaena FNR mod a kites ffie pres-ise nn erne interaction with the protein carriers ferredoxin Fd and flavodoxin Fld . Introduction of the shorter aspartic acid side-chain at position 139 produces an enzyee that interacts more weakly with both ET proteins. Moreover the removal of the charge as in the E139Q mutant or the charge-reversal mutation as in E139K FNR apparently enhances additional interaction modes of the enzyme with Fd and reduces the possible orientations with Fld to more productive and stronger ones. Hence removal of the negative charge at position 139 of Anabaena FNRproduces a deleterious effect in its ET reactions with Fd whereas it appears to enhance the ET processes with Fld. Significantly a large

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