Revisiting the Mechanism of the Anaerobic Coproporphyrinogen III Oxidase HemN

Article abstract of DOI:10.1002/anie.201814708

HemN is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the oxidative decarboxylation of coproporphyrinogen III to produce protoporphyrinogen IX, an intermediate in heme biosynthesis. HemN binds two SAM molecules in the active site, but how these two SAMs are utilized for the sequential decarboxylation of the two propionate groups of coproporphyrinogen III remains largely elusive. Provided here is evidence showing that in HemN catalysis a SAM serves as a hydrogen relay which mediates a radical-based hydrogen transfer from the propionate to the 5′-deoxyadenosyl (dAdo) radical generated from another SAM in the active site. Also observed was an unexpected shunt product resulting from trapping of the SAM-based methylene radical by the vinyl moiety of the mono-decarboxylated intermediate, harderoporphyrinogen. These results suggest a major revision of the HemN mechanism and reveal a new paradigm of the radical-mediated hydrogen transfer in radical SAM enzymology.

Full text of DOI:10.1002/anie.201814708

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Accepted Article
Title: Revisiting the mechanism of anaerobic coproporphyrinogen III
oxidases, a radical SAM enzyme involved in heme biosynthesis
Authors: Xinjian Ji, Tianlu Mo, Wan-Qiu Liu, Wei Ding, Zixin Deng, and
Qi Zhang
This manuscript has been accepted after peer review and appears as an
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201814708
Angew. Chem. 10.1002/ange.201814708
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Revisiting the mechanism of anaerobic coproporphyrinogen III
oxidases, a radical SAM enzyme involved in heme biosynthesis
Xinjian Ji, Tianlu Mo, Wan-Qiu Liu, Wei Ding, Zixin Deng, and Qi Zhang*
Abstract: HemN is
a
radical S-adenosyl-L-methionine (SAM)
although the possibility of an isomer of 2 produced from
decarboxylation of the second propionate group of 1 cannot be
excluded.[7] Using a series of deuterium-labeled substrates, they
identified an allyl-type radical as a result of hydrogen abstraction
from the β-position of the propionate side chain of 1.[7e] HemN
enzyme that catalyzes the oxidative decarboxylation of
coproporphyrinogen III to produce protoporphyrinogen IX, an
intermediate in heme biosynthesis. HemN binds two SAM molecules
in the active site, but how these two SAMs are utilized for the
sequential decarboxylation of the two propionate groups of
coproporphyrinogen III remains largely elusive. Here we provide
evidence supporting that in HemN catalysis, a SAM serves as a
hydrogen relay that mediates the radical-based hydrogen transfer
from the propionate to the 5ˊ-deoxyadenosyl (dAdo) radical
generated from another SAM in the active site. We also observed an
unexpected shunt product resulting from trapping of the SAM-based
methylene radical by the vinyl moiety of the mono-decarboxylated
intermediate, harderoporphyrinogen. These results require a major
revision of the HemN mechanism and reveal a new paradigm of the
radical-mediated hydrogen transfer in radical SAM enzymology.
binds two SAM molecules, and production of one molecule of 3
7c]
consumes two SAMs.[7b,
These observations led to the
mechanistic proposal shown in Figure 2. In this mechanism, the
dAdo radical produced from SAM cleavage abstracts the pro-S
hydrogen from the β-carbon of the propionate side chain to
produce a β-propionate radical, which undergoes fragmentation
to form the vinyl group (Figure 2). Cleavage of the second SAM
bound in the active site leads to formation of the second vinyl
group in a similar manner to resullt in 3 formation.
R1
coproporphyyrinogen III (1)
O
O
R2
R1
=
R2
R2
R2
=
=
=
NH HN
NH HN
OH
OH
OH
Heme is a ubiquitous cofactor in all kingdoms of life and plays
essential role in many fundamental biological processes, such
as respiration, photosynthesis, and the metabolism and
transport of oxygen.[1] The classical heme biosynthetic pathway
found in eukaryotes and most bacteria involves oxidative
decarboxylation of coproporphyrinogen III (1) to produce
protoporphyrinogen IX (3) (Figure 1).[2] This reaction is catalyzed
by coproporphyrinogen III oxidase (CPO), which exists in two
evolutionarily and mechanistically distinct families. The oxygen-
dependent CPO HemF requires molecular oxygen for activity,[3]
whereas the oxygen-independent CPO HemN[4] is an anaerobic
enzyme belonging to the radical S-adenosyl-L-methionine (SAM)
superfamily.[5]
harderoporpphyrinogen (2)
R1
O
=
3
protoporphyyrinogen IX ( )
R1
=
HOOC
COOH
Figure 1. Chemical structures of ccoprophophyrinogen III (1) and its
decarboxylated products produced by HeemN.
Although the mechanistic proposal shown in Figure 2 has
8]
been accepted for a long time,[5,
several issues remain
unanswered. Because binding of the second SAM (SAM #2) is
strictly essential for enzyme activity, as revealed by site-direct
mutagenesis,[7c] if both SAMs would be cleaved in the reaction,
how could one [4Fe-4S] cluster mediate the cleavage of two
SAMs bound at different positions? One hypothesis is that SAM
#2 is cleaved by electron transfer from the [4Fe-4S] cluster to
SAM #2 via the sulfonium center of the [4Fe-4S]-bound SAM
(SAM #1), and later SAM #1 is cleaved by the canonical radical
SAM chemistry.[7e] Another hypothesis is that SAM #2 serves as
a backup molecule and decarboxylation occurs only at the SAM
#1 site. After the first decarboxylation, SAM #2 enters into the
SAM #1 site and replaces the methionine and dAdoH products
resulting from SAM #1 cleavage.[5b] Although both hypotheses
are theoretically feasible, these involve significant movement of
SAM and porphyrinogen substrate in the enzyme active site,
which is not consistent with the delicate mechanisms observed
for many radical SAM enzymes in controlling the high reactivity
of radical intermediates during reaction.[5b]
Radical SAM superfamily is the largest known enzyme family
consisting of more than 110,000 members found in all three
domains of life.[5-6] These enzymes contain a [4Fe-4S] cluster to
bind SAM and reductively cleave its carbon-sulfur bond to
produce a highly reactive 5ˊ-deoxyadenosyl (dAdo) radical. This
alkyl radical then abstracts a hydrogen from the substrate to
produce 5ˊ-deoxyadenosine (dAdoH) and a second radical,
thereby leading to highly diverse reactions.[5]
The seminal work by Layer et al. showed that HemN catalyzes
the radical SAM-dependent oxidative decarboxylation of 1 in a
sequential manner, with the mono-decarboxylated product
harderoporphyrinogen (2) as an intermediate (Figure 1),
[*] X. Ji, Prof. Dr. W. Ding, Prof. Dr. Z. Deng, Prof. Dr. Q. Zhang
State Key Laboratory of Microbial Metabolism, School of Life Sciences
& Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240,
China
COO
H
COO
H
H
HH
H
H
dAdo
H3C
H
H
H
H
H3C
H
H3C
H
H
H
H
H
H
H
E-mail: qizhang@sioc.ac.cn
H
CO2, e-
NN
HH
N
N
H
dAdoH
R
R
R
X. Ji, T. Mo, Dr. W-Q. Liu, Prof. Dr. Q. Zhang
Department of Chemistry, Fudan University, Shanghai, 200433, China
Supporting information for this article is given via a link at the end of
the document.
H
H
R
H
R
H
R
Figure 2. The previously proposed mmechanism for the HemN-catalyzed
oxidative decarboxylation.
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arrow highlights deuterium incorporration into the resulting dAdoH;
approximately 30% of dAdoH is deuteriuum-labeled. Reactions were performed
by incubation of 1.5 μM HemN and 20 μMM coproporphyrinogen III with 400 μM
SAM or d3-SAM in the presence of 2 mmM sodium dithionate for 6 hrs. The
reactions were treated with H2O2 (1.5%) before LC-MS analysis.
To investigate the HemN mechanism, we first set out to obtain
its substrate 1. To this end, we knocked out hemN in E. coli and
grew the mutant strain in anaerobic condition, which
accumulated a small amount (1～2 mg/L) of coproporphyrin III
(4), the oxidized form of 1 (Figure 3A). 4 was extracted from the
mutant cells and purified by high performance liquid
chromatography (HPLC) (Supplementary Methods and Figure
S1-S2). Reduction of 4 to 1 was previously achieved by using
sodium amalgam,[7a, 9] which, unfortunately, is not commercially
available in China, prompting us to test alternative ways for 4
reduction. To our delight, we found that when the reaction was
performed with a relatively low concentration of 4 (< 50 μM),
quantitative production of 1 was observed by using NaBH4 as a
reductant at room temperature (Figure 3A).
We next tested the reaction with S-adenosyl-L-[methyl-2H3]-
methionine (d3-SAM). LC-HR-MS analysis of the reaction
mixture showed that both 2 and 3 were produced, but the
reaction efficiency is significantly lower than that with non-
deuterated SAM (the yields of 2 and 3 were approximately 20%
and 15%, respectively) (Figure 4A, trace iii). Importantly,
comparative MS analysis revealed apparent deuterium
incorporation into the dAdoH produced from the reaction with d3-
SAM (Figure 4B and 4C). These observations strongly argue
against the previous mechanism shown in Figure 2 and suggest
that dAdo radical produced from SAM #1 abstracts a hydrogen
from the methyl group of SAM #2 (or its derivative). Such a dAdo
radical-mediated hydrogen abstraction is consistent with the
apparent deuterium kinetic isotope effect observed in the
reaction (Figure 4A), and is reminiscent of recent studies on the
R
R
A
NaBH4
HN
N
NH
NH
N
HOOC
HOOC
HOOC
(for R = COOH)
HN
HN
NH
H2O2
HOOC
class
C
radical SAM methyltransferases,[10] which are
COOH
COOH
homologous to HemN.[11]
R = COOH, coproporphyrinogen III (1)
4
R = COOH, coproporphyrin III (
)
R = mSAM, 6
R = mSAM, 5
Intriguingly, careful analysis of HemN reaction revealed a
product (5) in the reaction with SAM, which exhibited a positive
charged molecular ion at m/z = 1013.4531 (calculated m/z =
1013.4550, 2.0 ppm for a molecular formula of C50H65N11O10S)
(Figure 5A and Figure S4A). HR-MS/MS analysis of 5 showed
two fragment ions at m/z = 250.09 and 136.06, which are
characteristic of the adenosine-containing compounds (Figure
3A and Figure S5).[12] A series of fragment ions (e.g. m/z =
331.17, 343.17, and 508.24) were also found for 5 (Figure 3B
and Figure S5), which are also present in the MS/MS spectrum
of 1 (Figure S2). These observations suggest that 5 contains an
adenosine moiety and a porphyrinogen ring, and hence are
likely a SAM adduct of 2 (Figure 3A). Similarly, a compound (5D)
exhibiting a molecular ion two mass unit more than 5 (observed
m/z = 1015.4642, calculated m/z = 1015.4675, 3.2 ppm for a
molecular formula of C50H63D2N11O10S) was observed in the
reaction with d3-SAM (Figure 5A and Figure S4B). 5D gave a set
fragment ions similar to those of 5 (Figure 3B and Figure S6),
suggesting 5D is a deuterium-labeled SAM adduct (Figure 3B). It
is noteworthy that in a recent report, a SAM adduct was also
observed in the reaction of C10P, a HemN homologous enzyme
required for forming the cyclopropane ring in CC-1065.[10k]
5D
R = mdSAM,
508.24
R = mdSAM, 6D
180.10
164.07
COOH
NH2
N
B
250.09
343.17
N
329.15
R1
R1
O
COOH
COOH
HOOC
N
N
S
HO
O
136.06
NH2
mSAM
OH OH
N
N
H
N
H
N
H
mdSAM
(R1 = H);
(R1 = D)
331.17
Figure 3. Porphyrin and porphyrinogen derivatives investigated in this study.
(A) Interconversion of porphyrin/porphyrinogen derivatives. (B) Common
fragment ions observed in the HR-MS/MS spectra of 1, 5 and 5D.
We then performed HemN reaction with 1, SAM, and sodium
dithionite, and the reaction mixture was analyzed by liquid
chromatography (LC)-high resolution (HR)-mass spectrometry
(MS). This analysis showed that both mono-decarboxylated
product, harderoporphyrinogen (2), and di-decarboxylated
product 3 were produced in the reaction mixture (Figure 4A,
trace i, and Figure S3). The result is consistent with the early
study by Layer and coworkers and confirms that the HemN-
catalyzed two-step decarboxylation is distributive.[7f]
Figure 4. HemN-catalyzed oxidative decarboxylation of 1. (A) LC-HR-MS
analysis of HemN reaction mixtures. The multiple selected ion monitoring (SIM)
mode includes [M + H]+ = 609.3 (corresponding to the oxidized form of 2) and
[M + H]+ = 563.3 (corresponding to the oxidized form of 3) for (i) reaction with
SAM, (ii) control reaction with SAM and boiled HemN, (iii) reaction with d3-
SAM, and (iv) control reaction with d3-SAM and boiled HemN. The MS spectra
of 2 and 3 were shown in Figure S3. (B) HR-MS spectra of dAdoH produced
from SAM. (C) HR-MS spectra of dAdoH produced from d3-SAM. The red
Figure 5. Characterization of the SAM aadduct in HemN reaction. (A) LC-HR-
MS analysis of HemN reaction miixture, showing the extracted ion
chromatograms (EICs) of [M + H]+
= 1013.5 (corresponding to 5) for (i)
reaction with SAM, and (ii) control reacttion with SAM and boiled HemN, and
the EICs of [M + H]+ = 1015.5 (correspoonding to 5D) for (iii) reaction with d3-
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10.1002/anie.201814708
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SAM, and (iv) control reaction with d3-SAM and boiled HemN. The MS spectra
of 5 and 5D were shown in Figure S4; the HR-MS/MS spectra of 5 and 5D
were shown in Figure S5 and Figure S6. (B) Structure of 6 and 6D (produced
by H2O2 oxidation of 5 and 5D) and the characteristic fragment ions observed
in HR-MS/MS analysis (see Figure S7 and Figure S8 for the detailed spectra).
Apparently, 5 is a shunt product resulting from trapping of the
radical intermediate 7 by the vinyl group of 2. Production of this
shunt product suggests that decarboxylation of both propionate
side chains occurs at the same site close to SAM #2, and after
the first decarboxylation, major conformational change of 2 is
required for the second decarboxylation. A working hypothesis
for HemN catalysis is shown in Figure 6B. The dAdo radical
generated from the cleavage of SAM #1 leads to a cascade of
hydrogen transfer to result in the formation of first vinyl side
chain on 2 (Figure 6B, II). 2 is likely released from the enzyme
and re-enters into the active site with a different, likely a flipped,
conformation, in which the second propionate group is placed
close to SAM #2 (Figure 6B, III). Such an out-and-in process of
2 is also consistent with the distributive action of HemN
observed previously[7f] and in this study. A new SAM (SAM #3)
enters into the active site and replaces Met and dAdoH by
binding to the [4Fe-4S] cluster, leading to the second
decarboxylation to produce 3 (Figure 6B, IV). As the out-and-in
process of 2 could be slow, cleavage of SAM #3 can happen
without a conformational change of 2 (Figure 6B, V), and in this
case, the SAM-based radical 7 can be trapped by the vinyl side
chain of 2 to generate the SAM adduct 5.
Because the porphyrinogen ring is easily fragmented during
MS/MS analysis and hence complicates spectrum interpretation,
we treated the reaction mixture with H2O2 to convert
porphyrinogen to the oxidized form (i.e. porphyrin) (Figure 3A),
which is more resistant to fragmentation. HR-MS/MS analysis of
6 and 6D (the oxidized form of 5 and 5D) gave a series of
fragment ions that clearly indicate that 6 and 6D are SAM
adducts of 4 (Figure 5B), supporting the proposed structure of 5
and 5D (Figure 3A).
Observation of the SAM adduct
5 provides valuable
mechanistic insights into HemN catalysis and suggests the
previously proposed mechanism should be significantly revised.
In contrast to the direct hydrogen abstraction from the
propionate side chain, the dAdo radical generated from SAM #1
cleavage abstracts a hydrogen from the methyl group of SAM #2
to produce a methylene radical 7 (Figure 6A). 7 then abstracts
the pro-S hydrogen from the propionate β-carbon to result in
decarboxylation. Because of multiple reaction turnovers in the
absence of specific electron acceptors, we propose that upon
decarboxylation the electron could go back to the [4Fe-4S]
cluster to reduce it to the active +1 state, similar to that proposed
for DesII catalysis.[13]
Radical SAM enzymes have evolved delicate systems to
control the generation and reactivity of radical species to
achieve specific catalytic outcomes.[5] However, because of the
extremely high reactivity of many radical species, the undesired
side reactions could still occur in some cases, as has been
extensively studied in reactions catalyzed by the Trp lyase
NosL.[14] Characterization of HemN mechanism and finding of
the unexpected SAM adduct further demonstrates the intriguing
mechanism and remarkable catalytic promiscuity of the radical
SAM superfamily enzymes, highlighting the great potential to
manipulate these enzymes for novel activities.
H
A
[4Fe-4S]2+
[4Fe-4S]+
CH3
dAdo
dAdoH
H
S
+
H
[4Fe-4S]+
[4Fe-4S]2+
H3C
R
R
SAM #2
SAM #1
N
H
CH2
CO2
COOH
H
H
COOH
H
S
+
H
H
H
H3C
R
H
R
H3C
7
Acknowledgements
R
N
H
N
R
H
This work is supported in part by grants from the National Key
Research and Development Program (2016 Y F A0501302), and
from National Natural Science Foundation of China (31600398 to
W.D., and 31670060 to Q.Z.), and from the Open Fund of Key
Laboratory of Glycoconjugate Research, Ministry of Public Health.
SAM #3
B
Met + dAdoH
SAM #3
Met + dAdoH
SAM #2
SAM #1
SAM #2
V
SAM #2
P
shunt path
P
P
P
V
V
I
II
1
2
2
out and in
Met + dAdoH
SAM #3
Keywords: Heme
• S-adenosylmethionine • biosynthesis •
decarboxylation • radical addition
Met + dAdoH
SAM #2
Met + dAdoH
SAM
V
References
SAM #2
P
V
P
V
V
III
IV
VI
[1] T. L. Poulos, Chem Rev 2014, 114, 3919-3962.
[2] a) I. U. Heinemann, M. Jahn, D. Jahhn, Arch Biochem Biophys 2008, 474,
5
3
2
238-251; b) H. A. Dailey, T. A. Daileyy, S. Gerdes, D. Jahn, M. Jahn, M. R.
O'Brian, M. J. Warren, Microbiol Moll Biol Rev 2017, 81.
Figure 6. The revised mechanism of HemN catalysis. (A) HemN reaction
utilizes SAM #2 (highlighted in a yellow eclipse) as a hydrogen rely for the
radical-mediated hydrogen transfer for oxidative decarboxylation of 1. (B) A
working hypothesis for the HemN catalysis. [4Fe-4S] cluster is represented as
a cube, and the porphyrinogen ring is represented as an orange diamond. P
and V represent propionate and vinyl moieties, respectively.
[3] a) T. Yoshinaga, S. Sano, J Biol Cheem 1980, 255, 4722-4726; b) A. E.
Medlock, H. A. Dailey, J Biol Chem 11996, 271, 32507-32510; c) D.
Breckau, E. Mahlitz, A. Sauerwald, GG. Layer, D. Jahn, J Biol Chem 2003,
278, 46625-46631; d) J. D. Phillips, F. G. Whitby, C. A. Warby, P. Labbe,
C. Yang, J. W. Pflugrath, J. D. Ferraara, H. Robinson, J. P. Kushner, C. P.
Hill, J Biol Chem 2004, 279, 38960-338968; e) D. S. Lee, E. Flachsova, M.
This article is protected by copyright. All rights reserved.

10.1002/anie.201814708
Angewandte Chemie International Edition
COMMUNICATION
Bodnarova, B. Demeler, P. Martasek, C. S. Raman, Proc Natl Acad Sci U
S A 2005, 102, 14232-14237.
[4] B. Troup, C. Hungerer, D. Jahn, J Bacteriol 1995, 177, 3326-3331.
[5] a) P. A. Frey, A. D. Hegeman, F. J. Ruzicka, Crit. Rev. Biochem. Mol. Biol.
2008, 43, 63-88; b) J. B. Broderick, B. R. Duffus, K. S. Duschene, E. M.
Shepard, Chem Rev 2014, 114, 4229-4317.
[6] a) J. A. Gerlt, J. T. Bouvier, D. B. Davidson, H. J. Imker, B. Sadkhin, D. R.
Slater, K. L. Whalen, Biochim Biophys Acta 2015, 1854, 1019-1037; b) B.
J. Landgraf, E. L. McCarthy, S. J. Booker, Annu Rev Biochem 2016, 85,
485-514.
Ding, Q. Zhang, Angew Chem Int Edd Engl 2018, 57, 6601-6604; f) B.
Wang, J. W. LaMattina, E. D. Baddinng, L. K. Gadsby, T. L. Grove, S. J.
Booker, Methods Enzymol 2018, 6006, 241-268; g) S. Hein, O. Klimmek, M.
Polly, M. Kern, J. Simon, Mol Microbbiol 2017, 104, 449-462; h) S. Hein, J.
V. Irmer, M. Gallei, R. Meusinger, J. Simon, Biochim Biophys Acta 2018;
i) Z. Zhang, N. Mahanta, G. A. Hudsson, D. A. Mitchell, W. A. van der Donk,
J Am Chem Soc 2017, 139, 18623-118631; j) N. Mahanta, Z. Zhang, G. A.
Hudson, W. A. van der Donk, D. A. MMitchell, J Am Chem Soc 2017, 139,
4310-4313; k) W. B. Jin, S. Wu, X. HH. Jian, H. Yuan, G. L. Tang, Nat
Commun 2018, 9, 2771.
[7] a) G. Layer, K. Verfurth, E. Mahlitz, D. Jahn, J Biol Chem 2002, 277,
34136-34142; b) G. Layer, J. Moser, D. W. Heinz, D. Jahn, W. D.
Schubert, EMBO J 2003, 22, 6214-6224; c) G. Layer, K. Grage, T.
Teschner, V. Schunemann, D. Breckau, A. Masoumi, M. Jahn, P.
Heathcote, A. X. Trautwein, D. Jahn, J Biol Chem 2005, 280, 29038-
29046; d) G. Layer, E. Kervio, G. Morlock, D. W. Heinz, D. Jahn, J. Retey,
W. D. Schubert, Biol Chem 2005, 386, 971-980; e) G. Layer, A. J. Pierik,
M. Trost, S. E. Rigby, H. K. Leech, K. Grage, D. Breckau, I. Astner, L.
Jansch, P. Heathcote, M. J. Warren, D. W. Heinz, D. Jahn, J Biol Chem
2006, 281, 15727-15734; f) K. Rand, C. Noll, H. M. Schiebel, D. Kemken,
T. Dulcks, M. Kalesse, D. W. Heinz, G. Layer, Biol Chem 2010, 391, 55-
63.
[11] a) Q. Zhang, W. A. van der Donk, WW. Liu, Acc. Chem. Res. 2012, 45, 555-
564; b) M. R. Bauerle, E. L. Schwalmm, S. J. Booker, J Biol Chem 2015,
290, 3995-4002.
[12] a) X. J. Ji, Y. Z. Li, Y. L. Jia, W. Dingg, Q. Zhang, Angew Chem Int Edit
2016, 55, 3334-3337; b) X. Ji, W. Q.. Liu, S. Yuan, Y. Yin, W. Ding, Q.
Zhang, Chem Commun 2016, 52, 100555-10558; c) X. Ji, Y. Li, L. Xie, H.
Lu, W. Ding, Q. Zhang, Angew Chemm Int Ed Engl 2016, 55, 11845-11848;
d) D. Mandalapu, X. Ji, Q. Zhang, BBiiochemistry 2019, 58, 36-39.
[13] M. W. Ruszczycky, S. H. Choi, H. WW. Liu, J Am Chem Soc 2010, 132,
2359-2369.
[14] a) Y. Nicolet, L. Zeppieri, P. Amara, J. C. Fontecilla-Camps, Angew Chem
Int Ed Engl 2014, 53, 11840-11844; b) D. M. Bhandari, H. Xu, Y. Nicolet,
J. C. Fontecilla-Camps, T. P. Begleyy, Biochemistry 2015, 54, 4767-4769;
c) X. Ji, Y. Li, W. Ding, Q. Zhang, Anngew Chem Int Ed Engl 2015, 54,
9021-9024; d) W. Ding, X. Ji, Y. Li, QQ. Zhang, Front Chem 2016, 4, 27; e)
D. M. Bhandari, D. Fedoseyenko, T.. P. Begley, Methods Enzymol 2018,
606, 155-178; f) D. M. Bhandari, D. Fedoseyenko, T. P. Begley, J Am
Chem Soc 2018, 140, 542-545; g) PP. Amara, J. M. Mouesca, M. Bella, L.
Martin, C. Saragaglia, S. Gambarellii, Y. Nicolet, J Am Chem Soc 2018,
140 16661-16668.
[8] B. Li, J. Bridwell-Rabb, Biochemistry 2019, 58, 85-93.
[9] B. Grandchamp, Y. Nordmann, Enzyme 1982, 28, 196-205.
[10] a) J. W. LaMattina, D. B. Nix, W. N. Lanzilotta, Proc Natl Acad Sci U S A
2016, 113, 12138-12143; bW. Ding, Y. Li, J. Zhao, X. Ji, T. Mo, H.
Qianzhu, Z. Deng, Y. Yu, F. Chen, Q. Zhang, Angew Chem Int Ed 2017,
56, 3857-3861; c) W. Ding, Y. Wu, X. Ji, H. Qianzhu, F. Chen, Z. Deng, Y.
Yu, Q. Zhang, Chem Commun 2017, 53, 5235-5238; d) J. W. LaMattina,
B. Wang, E. D. Badding, L. K. Gadsby, T. L. Grove, S. J. Booker, J Am
Chem Soc 2017, 139, 17438-17445; e) X. Ji, D. Mandalapu, J. Cheng, W.
.
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10.1002/anie.201814708
Angewandte Chemie International Edition
COMMUNICATION
COMMUNICATION
Text for Table of Contents
Xinjian Ji, Tianlu Mo, Wan-Qiu Liu, Ding
Wei, Zixin Deng, and Qi Zhang *
Page No. – Page No.
Revisiting the mechanism of
anaerobic coproporphyrinogen III
oxidases, a radical SAM enzyme
involved in heme biosynthesis
This article is protected by copyright. All rights reserved.