TY - JOUR
T1 - Detection and Characterization of Exchangeable Protons Bound to the Hydrogen-Activation Nickel Site of Desulfovibrio gigas Hydrogenase
T2 - A 1H and 2H Q-Band ENDOR Study
AU - Fan, Chaoliang
AU - Teixeira, Miguel
AU - Moura, Jose
AU - Moura, Isabel
AU - Huynh, Boi Hanh
AU - Gall, Jean Le
AU - Peck, Harry D.
AU - Hoffman, Brian M.
PY - 1991/1/1
Y1 - 1991/1/1
N2 - This paper presents a Q-band ENDOR study of the nickel site of the as-isolated (Ni-A), H2-reduced (Ni-C), and reoxidized (Ni-A/Ni-B) states of Desulfovibrio gigas hydrogenase. Through proton and deuteron ENDOR measurements we detect and characterize the possible products of heterolytic cleavage of H2, namely two distinct types of exchangeable protons, bound to the Ni-C site. One proton, H(l), has a hyperfine coupling, AH(1) = 16.8 MHz and appears to interact directly with Ni-C. The other proton, H(2), has AH(2) ≈ 4.4 MHz and could be associated with H20 or OH− bound to nickel. We discuss possible binding modes for H(l) and H(2). One type of exchangeable deuteron(s), D(2), associated with the Ni-C center remains associated with the Ni-B center after oxidation of the Ni-C. In addition we confirm that the Ni-A site is inaccessible to solvent protons.
AB - This paper presents a Q-band ENDOR study of the nickel site of the as-isolated (Ni-A), H2-reduced (Ni-C), and reoxidized (Ni-A/Ni-B) states of Desulfovibrio gigas hydrogenase. Through proton and deuteron ENDOR measurements we detect and characterize the possible products of heterolytic cleavage of H2, namely two distinct types of exchangeable protons, bound to the Ni-C site. One proton, H(l), has a hyperfine coupling, AH(1) = 16.8 MHz and appears to interact directly with Ni-C. The other proton, H(2), has AH(2) ≈ 4.4 MHz and could be associated with H20 or OH− bound to nickel. We discuss possible binding modes for H(l) and H(2). One type of exchangeable deuteron(s), D(2), associated with the Ni-C center remains associated with the Ni-B center after oxidation of the Ni-C. In addition we confirm that the Ni-A site is inaccessible to solvent protons.
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U2 - 10.1021/ja00001a003
DO - 10.1021/ja00001a003
M3 - Article
AN - SCOPUS:0026073745
SN - 0002-7863
VL - 113
SP - 20
EP - 24
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 1
ER -