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NiO nanoparticles and non-stoichiometric black NiO were shown to be effective sources of Ni ²⁺ ions causing sequence-selective peptide bond hydrolysis. NiO nanoparticles were as effective in this reaction as their...
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Cite this: Metallomics, 2020,
12,649
Peptide bond cleavage in the presence of
Ni-containing particles
Nina Ewa Wezynfeld, *
ab
Tomasz Fra˛czyk,
ac
Arkadiusz Bonna
d
and
Wojciech Bal *
a
NiO nanoparticles and non-stoichiometric black NiO were shown
to be effective sources of Ni
2+
ions causing sequence-selective
peptide bond hydrolysis. NiO nanoparticles were as effective in
this reaction as their molar equivalent of soluble Ni(II) salt. These
findings highlight the efficacy of delivery of toxic Ni
2+
by these
environmentally available particles.
The unique properties of nickel, including high melting point
and resistance to corrosion and oxidation are exploited in the
production of everyday objects such as coins, mobile phones,
kitchen utensils and cutlery,
1–4
e-cigarette lighters
5
as well as in
wind turbines
6
or in electric vehicles.
7
Behind the growing
demand for nickel-containing products, the numbers of people
allergic to nickel and developing cancers of the respiratory tract
are on the rise.
8–10
The molecular mechanisms behind these
diseases are not fully elucidated, but the ability of nickel
to hydrolyze proteins and peptides containing a specific
sequence Ser/Thr-Xaa-His could be an important step in their
development.
11–14
A number of human proteins, including histone
H2A,
15
annexins,
16
a-antitrypsin,
17
phospholipid scramblase 1,
18
and transcrition factors containing zinc finger domains
19,20
are
susceptible to the Ni(II)-dependent hydrolysis, resulting in their
deactivation.
17
Other transition metal ions, Cu
2+
and Pd
2+
,
14,21
were
also shown to drive the peptide bond cleavage via an analogous
mechanism of metal-dependent hydrolysis (MdH), presented in
Fig. 1. In brief: the susceptible peptide/protein site initially binds
the metal ion in a square-planar complex. Then, the N-terminal
fragment preceding the Ser residue is transferred to the hydroxyl
group of Ser forming an intermediate ester product (IP). Finally, the
ester is easily hydrolyzed to final products: the free N-terminal
fragment of the peptide/protein and the Ni(II)/Cu(II)/Pd(II) complex
with the C-terminal fragment.
12,21–23
Theproductsofthisreaction
are non-native (foreign) for the immune system and could initialize
the allergic response. On the other hand, the products of MdH were
shown to catalyze the production of Reactive Oxygen Species
(ROS),
15
involved in the cancer development.
Considering potential severe consequences of MdH for
human health, we decided to study this reaction in the
presence of Ni-containing particles, the poorly soluble forms
of nickel significantly present in human environment.
5,24,25
Their inhalation could result even in accumulating tens to
hundreds of micrograms of nickel in lung tissue as shown in
studies on nickel refinery workers
26
and experimental mice.
27
Ni nanoparticles could also easily penetrate the skin,
28
and be
deposited during tattooing, triggering allergic response.
29
Moreover, subcellular accumulation of Ni-containing particles,
for example in lysosomes or in mitochondria could signifi-
cantly enhance their dissolution and catalysis of ROS produc-
tion, respectively.
30–32
In our work we used four types of Ni-containing particles:
metallic (Ni metal) and three nickel oxides: stoichiometric
green nickel oxide (NiO green), non-stoichiometric black nickel
oxide (NiO black), and nickel oxide nanoparticles (NiO nano).
a
Institute of Biochemistry and Biophysics, Polish Academy of Sciences,
Pawin
´skiego 5a, 02-106 Warsaw, Poland. E-mail: wbal@ibb.waw.pl
b
Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3,
00-664, Warsaw, Poland. E-mail: nwezynfeld@ch.pw.edu.pl
c
Department of Immunology, Transplantology and Internal Medicine,
Medical University of Warsaw, Nowogrodzka 59, 02-006 Warsaw, Poland
d
Department of Biochemistry, University of Cambridge, Downing Site,
Tennis Court Road, Cambridge CB2 1QW, UK
Electronic supplementary information (ESI) available: Experimental section,
EDX results, determination of Ni
2+
concentration. See DOI: 10.1039/d0mt00070a
Received 18th March 2020,
Accepted 29th April 2020
DOI: 10.1039/d0mt00070a
rsc.li/metallomics
Significance to metallomics
Humankind are facing a growing incidence of nickel contact allergy and
respiratory tract cancers, possibly related to environmental exposure to
particulate nickel. In this work, we showed that poorly soluble Ni-
containing particles, the nickel forms we are mostly exposed to, could
effectively drive the cleavage of the peptide bond preceding the Ser/Thr-
Xaa-His motif present in many essential human proteins. Strikingly, NiO
nanoparticles were as effective hydrolytic agents as a soluble Ni(II) salt.
The products of this process could initiate the immune response and
increase the oxidative stress, thereby participating in initial steps of
allergy and cancer development.
Metallomics
COMMUNICATION
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650 |Metallomics, 2020, 12, 649--653 This journal is ©The Royal Society of Chemistry 20 20
Their images obtained by scanning electron microscopy (SEM)
are presented in Fig. 2.
The studied Ni-containing particles vary greatly. Ni metal
and NiO black particles are approximately spherical in shape,
but their surface is not perfectly smooth. There are a lot
of insets and dimples in their outer coat. On the other hand,
NiO green and NiO nano aggregated very easily in water
solution due to the relatively smooth surfaces. The linear
particle sizes did not usually exceed 10 mm, even for the largest
Ni metal and NiO black. Much smaller dimensions were noted
for NiO green, whose particles were limited to 1 mm. Despite the
NiO nano susceptibility to aggregation, the size of individual
particles was consistent with the manufacturer’s specification
(below 50 nm) and agreed with previous reports on the same
product.
33
Results of energy-dispersive X-ray (EDX) spectro-
scopy confirmed the high molar nickel fraction expected for
Ni metal (98%) and close to equimolar Ni : O ratio for
NiO particles of both types (detailed EDX results available in
Table S1, ESI). The amount of Ni
2+
released from the studied
particles in HEPES buffer at pH 7.4 was monitored over one-
week long incubation. During this time, small aliquots of
particle suspension were collected periodically, followed by
centrifugation to separate the supernatant from the particles,
and quantification of dissolved Ni
2+
ions by a spectroscopic
method based on the intensity of d–d band at 460 nm of stable
Ni(DTT) complexes.
34
The precise description of this method is
provided in ESIincluding Fig. S1 and S2. Its results were
positively verified by ICP-OES. According to data presented in
Fig. 3A, the highest concentration of Ni
2+
was observed for NiO
nano, followed by NiO black, ca. 6% and 2% of total Ni after a
week, respectively. It agrees with other studies on Ni
2+
release
from nano and micro Ni-containing particles.
The release rate was higher during the first eight hours of
the incubation. Much lower amounts of released Ni
2+
ions were
observed for NiO green and Ni metal, not exceeding 0.2% after
a week. The presence of the peptide did not affect the Ni
2+
release (see Fig. 3B and C). The promotion of Ni
2+
release by
proteins was noticed in several previous studies on stainless
steel.
33,35
Small size of the peptide and/or ten-fold molar excess
Fig. 2 SEM images of nickel particles: Ni metal (A), NiO green (B), NiO
black (C), NiO nanoparticles (D).
Fig. 3 (A) Concentration of Ni
2+
released from Ni-containing particles
containing 5.87 g l
1
Ni (equivalent to 100 mM Ni concentration after
the complete dissolution) in 100 mM HEPES, pH 7.4 and 37 1C. Kinetics of
Ni
2+
release from NiO nanoparticles (B) or non-stoichiometric black NiO
particles (C) containing 5.87 g l
1
Ni without (full symbols) and with (open
symbols) 1 mM Ac-GGASRHWKF-am (peptide), in 100 mM HEPES pH 7.4,
37 1C. Insets represent the kinetics from the first day of the incubation.
Fig. 1 The mechanism of Ni(II)-dependent hydrolysis of the peptide bond
preceding Ser in the R
1
-Ser-Xaa-His-Zaa-R
2
sequence, based on ref. 12, 14
and 23.
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of particulate nickel over the peptide could make this effect
unnoticeable here.
We also monitored the hydrolysis progression for samples
containing Ni-containing particles and Ac-GGASRHWKF-am by
HPLC-UV and ESI-MS. Results of this analysis are presented
in Fig. 4.
The fastest degradation of the peptidic substrate was
noticed in the presence of NiO nano, followed by NiO black.
Much smaller amounts of the substrate were degraded in the
suspensions of NiO green and Ni metal. A similar dependence
was demonstrated for the formation of final products and
intermediate product (IP). The IP fraction was negligible for
NiO green and Ni metal as the IP hydrolysis was faster than its
formation in the presence of these particles. Surprisingly,
despite the preceding relatively slow kinetics of Ni
2+
release
from the particles, all steps of MdH followed the pseudo-first-
order kinetics, used before for the description of MdH by
Ni
2+
salts. The values of substrate decay rate constants k
1
in
the presence of the particles were in the range of 0.069–4.0
10
5
s
1
, whereas k
2
values for IP hydrolysis were 1.9–3.4
10
5
s
1
. The differences in k
1
likely originated from differ-
ences in Ni
2+
concentration released by given particles. The
similarity of k
2
values was expected because this reaction step
did not depend on the Ni
2+
source, but only on the peptide
sequence and the pH (see Fig. 1). The range of k
2
values was
satisfactorily similar to that observed previously for a similar
peptide.
12
The overall MdH rates in the presence of NiO nano
and 10 mM Ni(NO
3
)
2
were very similar to each other, due to a
very effective Ni
2+
release from NiO nano, yielding the 1 mM
concentration equal to that of the peptide in less than one hour
and 4 mM Ni
2+
after 8 h (see Fig. 3). However, as the released
Ni
2+
content differed for different particles and varied during
the incubation even for a given particle type, we performed a
more detailed analysis on the k
1
dependence on Ni
2+
concen-
tration. We first calculated the amount of MdH-active 4N
complexes (step 1 in Fig. 1) for the released Ni
2+
concentration
at selected incubation times. The basis for these calculations
was provided by the species distribution of the analogous Ni(II)-
Ac-GASRHWKFL-am system.
12
The correctness of this approach
was corroborated by comparing the pH-dependence of Ni(II)
complexation by Ac-GGASRHWKF-am (from UV-vis spectro-
scopy) and by Ac-GASRHWKFL-am (from potentiometry). The
full consistency of these profiles shown in Fig. 5 confirmed that
differences in terminal residues did not affect the coordination
sphere of respective complexes.
The resulting concentrations of 4N complexes for MdH were
very low, between 0.2 and 15 mM depending on the particle type.
Then, considering that for 10 mM Ni
2+
1.67% of the peptide
was bound in 4N complexes, the determined k
1
= 4.17
10
5
s
1
led to the estimation of the theoretically maximal k
1
(where the whole peptide would be initially bound as the
hydrolytically active 4N complex) under given experimental
conditions
max
k
1
= 2.5 10
3
s
1
.
The obtained amounts of 4N complexes at different time of
incubation, together with the
max
k
1
value, allowed us to assess
the theoretical kinetics of peptide degradation in response to
time dependent Ni
2+
release. The results of these calculations
were compared with the experimentally determined amounts of
the degraded peptide for NiO nano and NiO black, as presented
in Fig. 6. The hydrolysis in the presence of NiO green and Ni
metal was not investigated in such fashion due to the very low
yield of those reactions.
The analysis demonstrated a very good correlation of the
experimental peptide fractions (rainbow circles) with those
expected from the calculations (rainbow lines). One could notice
that the fit of experimental points is closer to the theoretical
curves for the Ni
2+
concentration after longer (424 h) incubation
times, while signals measured for NiO black are more consistent
with the dependence expected after incubation for about 8 h.
Fig. 4 Kinetics of substrate decay (left), formation of intermediate pro-
duct (middle), and formation of final products (right) for metal-dependent
hydrolysis of 1 mM Ac-GGASRHWKF-am in the presence of particles
containing 5.87 g l
1
Ni or in the presence of 10 mM Ni(NO
3
)
2
in
100 mM HEPES, pH 7.4, 37 1C. The experimental data were fit to first
order kinetic equations.
Fig. 5 (A) UV-vis titration of 0.9 mM Ni(NO
3
)
2
and 0.95 mM Ac-GGASRHWKF-
am with concentrated NaOH. The spectra were codded with rainbow colors
from red (pH 4.5) to violet (pH 11.5), where the thicker orange line corresponds
to pH 7.4 and dotted grey line represents the spectrum of the peptide
alone. (B) The comparison of species distribution of previously studied
Ac-GASRHWKFL-am and Ni
2+
with the pH dependence of the formation of
the square-planar complex of Ni(II)-Ac-GGASRHWKF-am monitored by change
in the absorbance at 455 nm from the experiments, presented in (A).
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652 |Metallomics, 2020, 12, 649--653 This journal is ©The Royal Society of Chemistry 2020
However, considering experimental accuracy of determination
of Ni
2+
concentration, we did not find the differences between
the theoretical and experimental kinetics to be significant.
Therefore, the Ni
2+
release rate is the limiting factor for MdH
in the presence of Ni-containing particles.
Summarizing, our results indicate that Ni-containing parti-
cles, especially NiO nanoparticles and non-stoichiometric NiO
black, could be effective sources of Ni
2+
ions, leading to protein
degradation via MdH. The rate of this process is limited mostly
by the amount of released Ni
2+
ions. Due to the high number
of likely MdH targets,
22
the increasing human exposition to
Ni-containing objects and materials,
2
and the ability of NiO
nanoparticles to penetrate tissues
36
the protein hydrolysis in
the presence of poorly soluble Ni forms could be an important
contributor to nickel toxicity, including contact allergy and
respiratory cancers. Our test peptide was a relatively small
molecule. Therefore, we plan to continue these studies to
explore how the size and adsorption of proteinaceous MdH
targets and coincident biological molecules on the particles
could affect the studied reaction.
Conflicts of interest
There are no conflicts to declare.
Acknowledgements
This work was financed by Preludium Grant No. 2013/11/N/
NZ1/02400 (Polish National Science Centre) and in part
by TEAM No. 2009-4/1 grant (Foundation for Polish Science)
co-financed by the European Regional Development Fund
resources within the framework of Operational Program Inno-
vative Economy (Action 1.2). N. W. was supported by ETIUDA
scholarship No. 2015/16/T/NZ1/00377 (National Science Centre
of Poland). The equipment used was sponsored in part by the
Centre for Preclinical Research and Technology (CePT), a project
co-sponsored by European Regional Development Fund and
Innovative Economy, The National Cohesion Strategy of Poland.
References
1 J. P. Thyssen and T. Menne
´,Chem. Res. Toxicol., 2010, 23,
309–318.
2 M. G. Ahlstro
¨m, J. P. Thyssen, M. Wennervaldt, T. Menne
´
and J. D. Johansen, Contact Dermatitis, 2019, 81, 227–241.
3 C. R. Hamann, D. Hamann, C. Hamann, J. P. Thyssen and
C. Lide
´n, Contact Dermatitis, 2013, 68, 15–22.
4 P. Jensen, J. D. Johansen, C. Zachariae, T. Menne
´and
J. P. Thyssen, Contact Dermatitis, 2011, 65, 354–358.
5 M. Williams, A. Villarreal, K. Bozhilov, S. Lin and P. Talbot,
PLoS One, 2013, 8, e57987.
6 E. Robert, B. Robert and E. Rainer, Tribol. Trans., 2013, 56,
1069–1076.
7 G. Majeau-Bettez, T. R. Hawkins and A. H. StrØmman,
Environ. Sci. Technol., 2011, 45, 4548–4554.
8 P. M. de Groot, C. C. Wu, B. W. Carter and R. F. Munden,
Transl. Lung Cancer Res., 2018, 7, 220–233.
9 M. L. A. Schuttelaar, R. F. Ofenloch, M. Bruze, S. Cazzaniga,
P.Elsner,M.Gonçalo,L.Naldi.SvenssonandT.L.Diepgen,
Contact Dermatitis, 2018, 79,19.
10 D. N. Bhatta and S. A. Glantz, Am. J. Prev. Med., 2020, 58,
182–190.
11 A. Kre˛z˙el,E.Kopera,A.M.Protas,J.Poznan
´ski, A. Wysłouch-
Cieszyn
´ska and W. Bal, J. Am. Chem. Soc., 2010, 132, 3355–3366.
12 E. Kopera, A. Kre˛z˙el, A. M. Protas, A. Belczyk, A. Bonna,
A. Wysłouch-Cieszyn
´ska, J. Poznan
´ski and W. Bal, Inorg.
Chem., 2010, 49, 6636–6645.
13 A. M. Protas, H. H. Ariani, A. Bonna, A. Polkowska-
Nowakowska, J. Poznan
´ski and W. Bal, J. Inorg. Biochem.,
2013, 127, 99–106.
14 N. E. Wezynfeld, T. Fra
˛czyk and W. Bal, Coord. Chem. Rev.,
2016, 327-328, 166–187.
15 A. Karaczyn, W. Bal, S. L. North, R. M. Bare, V. M. Hoang,
R. J. Fisher and K. S. Kasprzak, Chem. Res. Toxicol., 2003, 16,
1555–1559.
16 N. E. Wezynfeld, K. Bossak, W. Goch, A. Bonna, W. Bal and
T. Fra˛czyk, Chem. Res. Toxicol., 2014, 27, 1996–2009.
17 N. E. Wezynfeld, A. Bonna, W. Bal and T. Fra˛czyk, Metallo-
mics, 2015, 7, 596–604.
18 T. Fra˛czyk, A. Bonna, E. Stefaniak, N. E. Wezynfeld and
W. Bal, Chem. Biodiversity, 2020, 17, e1900652.
19 E. Kurowska, J. Sasin-Kurowska, A. Bonna, M. Grynberg,
J. Poznan
´ski, L. Knizewski, K. Ginalski and W. Bal, Metal-
lomics, 2011, 3, 1227–1231.
20 A. Belczyk-Ciesielska, B. Csipak, B. Hajdu, A. Sparavier,
M. N. Asaka, K. Nagata, B. Gyurcsik and W. Bal, Metallomics,
2018, 10, 1089–1098.
21 A. Belczyk-Ciesielska, I. A. Zawisza, M. Mital, A. Bonna and
W. Bal, Inorg. Chem., 2014, 53, 4639–4646.
Fig. 6 The comparison of experimental kinetics of degradation of 1 mM
Ac-GGASRHWKF-am in the presence of NiO nano or NiO black containing
initially 5.87 g l
1
Ni (circles fitted with the first order kinetic equation
represented by a dashed grey line) with the theoretical kinetic curves
calculated from the concentrations of Ni
2+
released up to the indicated
time point. The circles representing the experimental substrate fraction at
different incubation times were marked by rainbow colors corresponding
to the colors of the theoretical kinetic curves.
Communication Metallomics
Downloaded from https://academic.oup.com/metallomics/article/12/5/649/5961826 by guest on 16 September 2021
This journal is ©The Royal Society of Chemistry 202 0 Metallomics, 2020, 12,649--653 | 653
22 N. E. Wezynfeld, T. Fra˛czyk and W. Bal, Coord. Chem. Rev.,
2016, 327–328, 166–187.
23 E. I. Podobas, A. Bonna, A. Polkowska-Nowakowska and
W. Bal, J. Inorg. Biochem., 2014, 136, 107–114.
24 B. A. Maher, I. A. M. Ahmed, V. Karloukovski, D. A. MacLaren,
P.G.Foulds,D.Allsop,D.M.A.Mann,R.Torres-Jardo
´nand
L. Calderon-Garciduenas, Proc.Natl.Acad.Sci.U.S.A., 2016,
113, 10797–10801.
25 E. Adamiec, E. Jarosz-Krzemin
´ska and R. Wieszała, Environ.
Monit. Assess., 2016, 188, 188–369.
26 H. J. Raithell, K. H. Schaller, A. Reith, K. B. Svenes and
H. Valentin, Int. Arch. Occup. Environ. Health, 1988, 60,
55–66.
27 J. M. Benson, I.-Y. Chang, Y. S. Cheng, F. F. Hahn,
C. H. Kennedy, E. B. Barr, K. R. Maples and M. B. Snipes,
Fundam. Appl. Toxicol., 1995, 28, 232–244.
28 M. Crosera, G. Adami, M. Mauro, M. Bovenzi, E. Baracchini
and F. Larese Filon, Chemosphere, 2016, 145, 301–306.
29 I. Schreiver, B. Hesse, C. Seim, H. Castillo-Michel, L. Anklamm,
J.Villanova,N.Dreiack,A.Lagrange,R.Penning,C.DeCuyper,
R. Tucoulou, W. Ba
¨umler, M. Cotte and A. Luch, Part. Fibre
Toxicol., 2019, 16,110.
30 S. Latvala, J. Hedberg, S. Di Bucchianico, L. Mo
¨ller,
I. O. Wallinder, K. Elihn and H. L. Karlsson, PLoS One,
2016, 11, 1–20.
31 N. Shinohara, G. Zhang, Y. Oshima, T. Kobayashi,
N. Imatanaka, M. Nakai, T. Sasaki, K. Kawaguchi and
M. Gamo, Part. Fibre Toxicol., 2017, 14(48), 1–14, DOI:
10.1186/s12989-017-0229-x.
32 S. Z. Abdulqadir and F. M. Aziz, Int. J. Nanomed., 2019, 14,
3995–4005.
33 Y. Hedberg, M. E. Karlsson, Z. Wei, M. Z
ˇnidars
ˇic
ˇ, I. Odnevall
Wallinder and J. Hedberg, Corrosion, 2017, 73, 1423–1436.
34 A. Kre˛z˙el, W. Les
´niak, M. Jez˙owska-Bojczuk, P. Młynarz,
J. Brasun
´, H. Kozłowski and W. Bal, J. Inorg. Biochem.,2001,
84, 77–88.
35 Y. S. Hedberg, npj Mater. Degrad., 2018, 2, 1–5.
36 A. Marzban, B. Seyedalipour, M. Mianabady, A. Taravati and
S. M. Hoseini, Biol. Trace Elem. Res., 2020, DOI: 10.1007/
s12011-019-01941-x.
Metallomics Communication
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... We chose physiological temperature (37 • C) and two pH values, 7.4 and 8.2, close to those existing in cytoplasm and mitochondria, respectively. Such pH values were also used in our previous publications [17,[19][20][21]39]. Thus, it is also possible to compare the measured hydrolysis rates with other peptides. ...
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