 |
PDBsum entry 1xdc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Oxidoreductase
|
PDB id
|
|
|
|
1xdc
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
References listed in PDB file
|
|
|
Key reference
|
|
|
Title
|
|
Hydrogen bonding in human manganese superoxide dismutase containing 3-Fluorotyrosine.
|
|
|
Authors
|
|
I.Ayala,
J.J.Perry,
J.Szczepanski,
J.A.Tainer,
M.T.Vala,
H.S.Nick,
D.N.Silverman.
|
|
|
Ref.
|
|
Biophys J, 2005,
89,
4171-4179.
|
|
|
PubMed id
|
|
|
|
|
|
Abstract
|
|
|
Incorporation of 3-fluorotyrosine and site-specific mutagenesis has been
utilized with Fourier transform infrared (FTIR) spectroscopy and x-ray
crystallography to elucidate active-site structure and the role of an
active-site residue Tyr34 in human manganese superoxide dismutase (MnSOD).
Calculated harmonic frequencies at the B3LYP/6-31G** level of theory for
L-tyrosine and its 3-fluorine substituted analog are compared to experimental
frequencies for vibrational mode assignments. Each of the nine tyrosine residues
in each of the four subunits of the homotetramer of human MnSOD was replaced
with 3-fluorotyrosine. The crystal structures of the unfluorinated and
fluorinated wild-type MnSOD are nearly superimposable with the root mean-square
deviation for 198 alpha-carbon atoms at 0.3 A. The FTIR data show distinct
vibrational modes arising from 3-fluorotyrosine in MnSOD. Comparison of spectra
for wild-type and Y34F MnSOD showed that the phenolic hydroxyl of Tyr34 is
hydrogen bonded, acting as a proton donor in the active site. Comparison with
crystal structures demonstrates that the hydroxyl of Tyr34 is a hydrogen bond
donor to an adjacent water molecule; this confirms the participation of Tyr34 in
a network of residues and water molecules that extends from the active site to
the adjacent subunit.
|
|
|
|
|
|
|
