TY - JOUR
T1 - Probing the structural basis for enzyme-substrate recognition in cu, zn superoxide dismutase
AU - Fisher, Cindy L.
AU - Hallewell, Robert A.
AU - Roberts, Victoria A.
AU - Tainer, John A.
AU - Getzoff, Elizabeth D.
N1 - Funding Information:
This work was funded in part by the National Institutes of Health Grants GM 39345 (to J.A.T.), GM 37684 (to E.D.G.), and fellowship GM I1612 (to C.L.F.).
PY - 1991
Y1 - 1991
N2 - A full understanding of enzyme-substrate interactions requires a detailed knowledge of their structural basis at atomic resolution. Crystallographic and biochemical data have been analyzed with coupled computational and computer graphic approaches to characterize the molecular basis for recognition of the superoxide anion substrate by Cu. Zn superoxide dismutase (SOD). Detailed analysis of the bovine SOD structure aligned with SOD sequences from 15 species provides new results concerning the significance and molecular basis for sequence conservation. Specific roles have been assigned for all 23 invariant residues and additional residues exhibiting functional equivalence. Sequence invariance is dominated by 15 residues that form the active site stcreochemistry. supporting a primary biological function of superoxide dismutation. Using data from crystallographic structures and site-directed mutants, we are testing the role of individual residues in the active site channel, including (in human SOD) Glu132, Glu133, Lys136, Thr137, and Arg 143. Electrostatic calculations incorporating molecular flexibility suggest that the region of positive electrostatic potential in and over the active site channel above the Cu ion sweeps through space during molecular motion to enhance the facilitated diffusion responsible for the enzyme's rapid catalytic rate.
AB - A full understanding of enzyme-substrate interactions requires a detailed knowledge of their structural basis at atomic resolution. Crystallographic and biochemical data have been analyzed with coupled computational and computer graphic approaches to characterize the molecular basis for recognition of the superoxide anion substrate by Cu. Zn superoxide dismutase (SOD). Detailed analysis of the bovine SOD structure aligned with SOD sequences from 15 species provides new results concerning the significance and molecular basis for sequence conservation. Specific roles have been assigned for all 23 invariant residues and additional residues exhibiting functional equivalence. Sequence invariance is dominated by 15 residues that form the active site stcreochemistry. supporting a primary biological function of superoxide dismutation. Using data from crystallographic structures and site-directed mutants, we are testing the role of individual residues in the active site channel, including (in human SOD) Glu132, Glu133, Lys136, Thr137, and Arg 143. Electrostatic calculations incorporating molecular flexibility suggest that the region of positive electrostatic potential in and over the active site channel above the Cu ion sweeps through space during molecular motion to enhance the facilitated diffusion responsible for the enzyme's rapid catalytic rate.
KW - Electrostatics
KW - Evolution
KW - Mutants
KW - Structure-function
KW - Superoxide dismutase
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U2 - 10.3109/10715769109145797
DO - 10.3109/10715769109145797
M3 - Article
C2 - 1649096
AN - SCOPUS:0025930452
SN - 1071-5762
VL - 12
SP - 287
EP - 296
JO - Free Radical Research
JF - Free Radical Research
IS - 1
ER -