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Title:
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Structure-function analysis of yeast Grx5 monothiol glutaredoxin defines essential amino acids for the function of the protein
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Author:
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Bellí i Martínez, Gemma; Polaina, Julio; Tamarit Sumalla, Jordi; Torre Ruiz, M. A. de la; Rodríguez Manzanaque, Maria Teresa; Ros Salvador, Joaquim; Herrero Perpiñán, Enrique
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Notes:
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Grx5 defines a family of yeast monothiol glutaredox-
ins that also includes Grx3 and Grx4. All three proteins
display significant sequence homology with proteins
found from bacteria to humans. Grx5 is involved in iron/
sulfur cluster assembly at the mitochondria, but the
function of Grx3 and Grx4 is unknown. Three-dimen-
sional modeling based on known dithiol glutaredoxin
structures predicted a thioredoxin fold structure for
Grx5. Positionally conserved amino acids in this glu-
taredoxin family were replaced in Grx5, and the effect
on the biological function of the protein has been tested.
For all changes studied, there was a correlation between
the effects on several different phenotypes: sensitivity
to oxidants, constitutive protein oxidation, ability for
respiratory growth, auxotrophy for a number of amino
acids, and iron accumulation. Cys60 and Gly61 are essen-
tial for Grx5 function, whereas other single or double
substitutions in the same region had no phenotypic ef-
fects. Gly115 and Gly116 could be important for the for-
mation of a glutathione cleft on the Grx5 surface, in
contrast to adjacent Cys117. Substitution of Phe50 alters
the -sheet in the thioredoxin fold structure and inhib-
its Grx5 function. None of the substitutions tested affect
the structure at a significant enough level to reduce
protein stability. |
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Rights:
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(c) The American Society for Biochemistry and Molecular Biology, 2002
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Document type:
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article
publishedVersion |
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Published by:
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The American Society for Biochemistry and Molecular Biology
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