93. Yang H, Rittle J, Marts AR, Peters JC, Hoffman BM (2018) ENDOR characterization of
(N 2 )Fe
II
(l-H) 2 Fe
I
(N 2 )
-
: A spectroscopic model for N 2 binding by the di-l-hydrido
nitrogenase Janus intermediate. Inorg Chem 57(19):12323–12330
94. Burgess BK, Wherland S, Newton WE, Stiefel EI (1981) Nitrogenase reactivity: insight into
the nitrogen-fixing process through hydrogen-inhibition and HD-forming reactions.
Biochemistry 20(18):5140–5146
95. Jensen BB, Burris RH (1985) Effect of high pN 2 and high pD 2 on NH 3 production, H 2
evolution, and HD formation by nitrogenases. Biochemistry 24(5):1141–1147
96. Fisher K, Dilworth MJ, Newton WE (2000) Differential effects on N 2 binding and reduction,
HD formation, and azide reduction with a-195
His - and a-191
Gln -substituted MoFe proteins
of Azotobacter vinelandii nitrogenase. Biochemistry 39(50):15570–15577
97. Yang ZY, Khadka N, Lukoyanov D, Hoffman BM, Dean DR, Seefeldt LC (2013) On
reversible H 2 loss upon N 2 binding to FeMo-cofactor of nitrogenase. Proc Natl Acad Sci U S
A 110(41):16327–16332
98. Chatt J, Pearman AJ, Richards RL (1975) The reduction of mono-coordinated molecular
nitrogen to ammonia in a protic environment. Nature 253:39–40
99. Yandulov DV, Schrock RR (2003) Catalytic reduction of dinitrogen to ammonia at a single
molybdenum center. Science 301(5629):76–78
100. Thorneley RNF, Eady RR, Lowe DJ (1978) Biological nitrogen fixation by way of an
enzyme-bound dinitrogen-hydride intermediate. Nature 272:557–558
101. Davis LC (1980) Hydrazine as a substrate and inhibitor of Azotobacter vinelandii
nitrogenase. Arch Biochem Biophys 204(1):270–276
102. Barney BM, McClead J, Lukoyanov D et al (2007) Diazene (HN=NH) is a substrate for
nitrogenase: insights into the pathway of N 2 reduction. Biochemistry 46(23):6784–6794
103. Barney BM, Yang TC, Igarashi RY et al (2005) Intermediates trapped during nitrogenase
reduction of N triple bond N, CH 3 -N=NH, and H 2 N–NH 2 . J Am Chem Soc 127(43):14960–
14961
104. Lukoyanov D, Dikanov SA, Yang ZY et al (2011) ENDOR/HYSCORE studies of the
common intermediate trapped during nitrogenase reduction of N 2 H 2 , CH 3 N 2 H, and N 2 H 4
support an alternating reaction pathway for N 2 reduction. J Am Chem Soc 133(30):11655–
11664
105. Lukoyanov D, Yang ZY, Barney BM, Dean DR, Seefeldt LC, Hoffman BM (2012)
Unification of reaction pathway and kinetic scheme for N 2 reduction catalyzed by
nitrogenase. Proc Natl Acad Sci U S A 109(15):5583–5587
106. Spatzal T, Perez KA, Einsle O, Howard JB, Rees DC (2014) Ligand binding to the
FeMo-cofactor: structures of CO-bound and reactivated nitrogenase. Science 345
(6204):1620–1623
107. Sippel D, Rohde M, Netzer J et al (2018) A bound reaction intermediate sheds light on the
mechanism of nitrogenase. Science 359(6383):1484–1489
108. Benediktsson B, Thorhallsson AT, Bjornsson R (2018) QM/MM calculations reveal a
bridging hydroxo group in a vanadium nitrogenase crystal structure. Chem Commun (Camb)
54(53):7310–7313
109. Spatzal T, Perez KA, Howard JB, Rees DC (2015) Catalysis-dependent selenium
incorporation and migration in the nitrogenase active site iron-molybdenum cofactor. Elife
4:e11620
184
C.-C. Lee et al.
(N 2 )Fe
II
(l-H) 2 Fe
I
(N 2 )
-
: A spectroscopic model for N 2 binding by the di-l-hydrido
nitrogenase Janus intermediate. Inorg Chem 57(19):12323–12330
94. Burgess BK, Wherland S, Newton WE, Stiefel EI (1981) Nitrogenase reactivity: insight into
the nitrogen-fixing process through hydrogen-inhibition and HD-forming reactions.
Biochemistry 20(18):5140–5146
95. Jensen BB, Burris RH (1985) Effect of high pN 2 and high pD 2 on NH 3 production, H 2
evolution, and HD formation by nitrogenases. Biochemistry 24(5):1141–1147
96. Fisher K, Dilworth MJ, Newton WE (2000) Differential effects on N 2 binding and reduction,
HD formation, and azide reduction with a-195
His - and a-191
Gln -substituted MoFe proteins
of Azotobacter vinelandii nitrogenase. Biochemistry 39(50):15570–15577
97. Yang ZY, Khadka N, Lukoyanov D, Hoffman BM, Dean DR, Seefeldt LC (2013) On
reversible H 2 loss upon N 2 binding to FeMo-cofactor of nitrogenase. Proc Natl Acad Sci U S
A 110(41):16327–16332
98. Chatt J, Pearman AJ, Richards RL (1975) The reduction of mono-coordinated molecular
nitrogen to ammonia in a protic environment. Nature 253:39–40
99. Yandulov DV, Schrock RR (2003) Catalytic reduction of dinitrogen to ammonia at a single
molybdenum center. Science 301(5629):76–78
100. Thorneley RNF, Eady RR, Lowe DJ (1978) Biological nitrogen fixation by way of an
enzyme-bound dinitrogen-hydride intermediate. Nature 272:557–558
101. Davis LC (1980) Hydrazine as a substrate and inhibitor of Azotobacter vinelandii
nitrogenase. Arch Biochem Biophys 204(1):270–276
102. Barney BM, McClead J, Lukoyanov D et al (2007) Diazene (HN=NH) is a substrate for
nitrogenase: insights into the pathway of N 2 reduction. Biochemistry 46(23):6784–6794
103. Barney BM, Yang TC, Igarashi RY et al (2005) Intermediates trapped during nitrogenase
reduction of N triple bond N, CH 3 -N=NH, and H 2 N–NH 2 . J Am Chem Soc 127(43):14960–
14961
104. Lukoyanov D, Dikanov SA, Yang ZY et al (2011) ENDOR/HYSCORE studies of the
common intermediate trapped during nitrogenase reduction of N 2 H 2 , CH 3 N 2 H, and N 2 H 4
support an alternating reaction pathway for N 2 reduction. J Am Chem Soc 133(30):11655–
11664
105. Lukoyanov D, Yang ZY, Barney BM, Dean DR, Seefeldt LC, Hoffman BM (2012)
Unification of reaction pathway and kinetic scheme for N 2 reduction catalyzed by
nitrogenase. Proc Natl Acad Sci U S A 109(15):5583–5587
106. Spatzal T, Perez KA, Einsle O, Howard JB, Rees DC (2014) Ligand binding to the
FeMo-cofactor: structures of CO-bound and reactivated nitrogenase. Science 345
(6204):1620–1623
107. Sippel D, Rohde M, Netzer J et al (2018) A bound reaction intermediate sheds light on the
mechanism of nitrogenase. Science 359(6383):1484–1489
108. Benediktsson B, Thorhallsson AT, Bjornsson R (2018) QM/MM calculations reveal a
bridging hydroxo group in a vanadium nitrogenase crystal structure. Chem Commun (Camb)
54(53):7310–7313
109. Spatzal T, Perez KA, Howard JB, Rees DC (2015) Catalysis-dependent selenium
incorporation and migration in the nitrogenase active site iron-molybdenum cofactor. Elife
4:e11620
184
C.-C. Lee et al.