We examine the use of the truncated singular value decomposition and Tikhonov regularization in standard form to address ill-posed least squares problems Ax = b that frequently arise in molecular mechanics force field parameter optimization. We illustrate these approaches by applying them to dihedral parameter optimization of genotoxic polycyclic aromatic hydrocarbon-DNA adducts that are of interest in the study of chemical carcinogenesis. Utilizing the discrete Picard condition and/or a well-defined gap in the singular value spectrum when A has a well-determined numerical rank, we are able to systematically determine truncation and in turn regularization parameters that are correspondingly used to produce truncated and regularized solutions to the ill-posed least squares problem at hand. These solutions in turn result in optimized force field dihedral terms that accurately parameterize the torsional energy landscape. As the solutions produced by this approach are unique, it has the advantage of avoiding the multiple iterations and guess and check work often required to optimize molecular mechanics force field parameters.

1.
K.
Vanommeslaeghe
,
E.
Hatcher
,
C.
Acharya
,
S.
Kundu
,
S.
Zhong
,
J.
Shim
,
E.
Darian
,
O.
Guvench
,
P.
Lopes
,
I.
Vorobyov
, and
A. D.
Mackerell
, Jr.
, “
CHARMM general force field: A force field for drug-like molecules compatible with the CHARMM all-atom additive biological force fields
,”
J. Comput. Chem.
31
,
671
690
(
2010
).
2.
K.
Vanommeslaeghe
and
A. D.
MacKerell
, Jr.
, “
Automation of the CHARMM general force field (CGenFF) I: Bond perception and atom typing
,”
J. Chem. Inf. Model.
52
,
3144
3154
(
2012
).
3.
K.
Vanommeslaeghe
,
E. P.
Raman
, and
A. D.
MacKerell
, Jr.
, “
Automation of the CHARMM general force field (CGenFF) II: Assignment of bonded parameters and partial atomic charges
,”
J. Chem. Inf. Model.
52
,
3155
3168
(
2012
).
4.
C. G.
Mayne
,
J.
Saam
,
K.
Schulten
,
E.
Tajkhorshid
, and
J. C.
Gumbart
, “
Rapid parameterization of small molecules using the force field toolkit
,”
J. Comput. Chem.
34
,
2757
2770
(
2013
).
5.
A. D.
MacKerell
, “
The CHARMM force field-CECAM workshop: Advances in biomolecular modelling and simulations using CHARMM
,” University College Dublin, Ireland June 5-8, 2012 (accessed September 2, 2020), see http://mackerell.umaryland.edu/ kenno/cgenff/downloader.php?filename=CHARMM_FF_Mackerell4.pdf.
6.
J.
Wang
,
R. M.
Wolf
,
J. W.
Caldwell
,
P. A.
Kollman
, and
D. A.
Case
, “
Development and testing of a general amber force field
,”
J. Comput. Chem.
25
,
1157
1174
(
2004
).
7.
J.
Wang
,
W.
Wang
,
P. A.
Kollman
, and
D. A.
Case
, “
Automatic atom type and bond type perception in molecular mechanical calculations
,”
J. Mol. Graphics Modell.
25
,
247
260
(
2006
).
8.
V.
Zoete
,
M. A.
Cuendet
,
A.
Grosdidier
, and
O.
Michielin
, “
SwissParam: A fast force field generation tool for small organic molecules
,”
J. Comput. Chem.
32
,
2359
2368
(
2011
).
9.
A.
Kumar
,
O.
Yoluk
, and
A. D.
MacKerell
, Jr.
, “
FFParam: Standalone package for CHARMM additive and Drude polarizable force field parametrization of small molecules
,”
J. Comput. Chem.
41
,
958
970
(
2020
).
10.
S.
Dasgupta
,
T.
Yamasaki
, and
W. A.
Goddard
 III
, “
The Hessian biased singular value decomposition method for optimization and analysis of force fields
,”
J. Chem. Phys.
104
,
2898
2920
(
1996
).
11.
O.
Guvench
and
A. D.
MacKerell
, “
Automated conformational energy fitting for force-field development
,”
J. Mol. Model.
14
,
667
679
(
2008
).
12.
K.
Vanommeslaeghe
,
M.
Yang
, and
A. D.
Mackerell
, “
Robustness in the fitting of molecular mechanics parameters
,”
J. Comput. Chem.
36
,
1083
1101
(
2015
).
13.
C. W.
Hopkins
and
A. E.
Roitberg
, “
Fitting of dihedral terms in classical force fields as an analytic linear least-squares problem
,”
J. Chem. Inf. Model.
54
,
1978
1986
(
2014
).
14.
G.
Golub
and
C.
Van Loan
,
Matrix Computations
(
Johns Hopkins University Press
,
Baltimore
,
1996
).
15.
J.
Demmel
,
Applied Numerical Linear Algebra
(
SIAM
,
Philadelphia
,
1997
).
16.
L.
Eldén
, “
Algorithms for regularization of ill-conditioned least squares problems
,”
BIT Numer. Math.
17
,
134
145
(
1977
).
17.
P. C.
Hansen
, “
The truncated SVD as a method for regularization
,”
BIT Numer. Math.
27
,
534
553
(
1987
).
18.
P. C.
Hansen
, “
Truncated singular value decomposition solutions to discrete ill-posed problems with ill-determined numerical rank
,”
SIAM J. Sci. Stat. Comput.
11
,
503
518
(
1990
).
19.
A. N.
Tikhonov
, “
Solution of incorrectly formulated problems and the regularization method
,”
Dokl. Akad. Nauk SSSR
151
,
501
504
(
1963
); available at http://mi.mathnet.ru/eng/dan28329
20.
D. L.
Phillips
, “
A technique for the numerical solution of certain integral equations of the first kind
,”
J. Assoc. Comput. Mach.
9
,
84
97
(
1962
).
21.
D. J.
Urwin
and
A. N.
Alexandrova
, “
Dihedral parameterization of PAH-DNA adduct covalent bonds in the CHARMM molecular mechanics force field
” (submitted) (
2020
).
22.
A.
Luch
, “
On the impact of the molecule structure in chemical carcinogenesis
,” in
Molecular, Clinical and Environmental Toxicology. Volume 1: Molecular Toxicology
, edited by
A.
Luch
(
Birkhäuser Verlag
,
2009
), pp.
151
178
.
23.
S.
Broyde
,
L.
Wang
,
Y.
Cai
,
L.
Jia
,
R.
Shapiro
,
D. J.
Patel
, and
N. E.
Geacintov
, “
Covalent polycyclic aromatic hydrocarbon–DNA adducts: Carcinogenicity, structure, and function
,” in
Chemical Carcinogenesis
, edited by
T. M.
Penning
(
Springer
,
2011
), Chap. 9, pp.
181
207
.
24.
M.
Cosman
,
R.
Fiala
,
B. E.
Hingerty
,
A.
Laryea
,
H.
Lee
,
R. G.
Harvey
,
S.
Amin
,
N. E.
Geacintov
,
S.
Broyde
, and
D.
Patel
, “
Solution conformation of the (+)-trans-anti-[BPh]dA adduct opposite dT in a DNA duplex: Intercalation of the covalently attached benzo[c]phenanthrene to the 5′-side of the adduct site without disruption of the modified base pair
,”
Biochemistry
32
,
12488
12497
(
1993
).
25.
M.
Cosman
,
A.
Laryea
,
R.
Fiala
,
B. E.
Hingerty
,
S.
Amin
,
N. E.
Geacintov
,
S.
Broyde
, and
D. J.
Patel
, “
Solution conformation of the (−)-trans-anti-benzo[c]phenanthrene-dA ([BPh]dA) adduct opposite dT in a DNA duplex: Intercalation of the covalently attached benzo[c]phenanthrenyl ring to the 3′-side of the adduct site and comparison with the (+)-trans-anti-[BPh]dA opposite dT stereoisomer
,”
Biochemistry
34
,
1295
1307
(
1995
).
26.
E. J.
Schurter
,
J. M.
Sayer
,
T.
Oh-hara
,
H. J. E.
Yeh
,
H.
Yagi
,
B. A.
Luxon
,
D. M.
Jerina
, and
D. G.
Gorenstein
, “
Nuclear magnetic resonance solution structure of an undecanucleotide duplex with a complementary thymidine base opposite a 10R adduct derived from trans addition of a deoxyadenosine N6-amino group to (−)-(7R,8S,9R,10S)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene
,”
Biochemistry
34
,
9009
9020
(
1995
).
27.
Y.
Cai
,
S.
Ding
,
N. E.
Geacintov
, and
S.
Broyde
, “
Intercalative conformations of the 14R(+)- and 14S(−)- trans-anti-DB[a,l]P-N6-dA adducts: Molecular modeling and MD simulations
,”
Chem. Res. Toxicol.
24
,
522
531
(
2011
).
28.
Y.
Cai
,
N. E.
Geacintov
, and
S.
Broyde
, “
Nucleotide excision repair efficiencies of bulky carcinogen-DNA adducts are governed by a balance between stabilizing and destabilizing interactions
,”
Biochemistry
51
,
1486
1499
(
2012
).
29.
H.
Mu
,
N. E.
Geacintov
,
Y.
Zhang
, and
S.
Broyde
, “
Recognition of damaged DNA for nucleotide excision repair: A correlated motion mechanism with a mismatched cis-syn thymine dimer lesion
,”
Biochemistry
54
,
5263
5267
(
2015
).
30.
H.
Mu
,
N. E.
Geacintov
,
J.-H.
Min
,
Y.
Zhang
, and
S.
Broyde
, “
Nucleotide excision repair lesion-recognition protein Rad4 captures a pre-flipped partner base in a benzo[a]pyrene-derived DNA lesion: How structure impacts the binding pathway
,”
Chem. Res. Toxicol.
30
,
1344
1354
(
2017
).
31.
N. E.
Geacintov
and
S.
Broyde
, “
Repair-resistant DNA lesions
,”
Chem. Res. Toxicol.
30
,
1517
1548
(
2017
).
32.
C. L.
Lawson
and
R. J.
Hanson
,
Solving Least Squares Problems
(
Prentice-Hall
,
Englewood Cliffs, NJ
,
1974
).
33.
J. M.
Varah
, “
On the numerical solution of ill-conditioned linear systems with applications to ill-posed problems
,”
SIAM J. Numer. Anal.
10
,
257
267
(
1973
).
34.
J. M.
Varah
, “
A practical examination of some numerical methods for linear discrete ill-posed problems
,”
SIAM Rev.
21
,
100
111
(
1979
).
35.
J. M.
Varah
, “
Pitfalls in the numerical solution of linear ill-posed problems
,”
SIAM J. Sci. Stat. Comput.
4
,
164
176
(
1983
).
36.
J. T.
Andersson
and
C.
Achten
, “
Time to say goodbye to the 16 EPA PAHs? Toward an up-to-date use of PACs for environmental purposes
,”
Polycyclic Aromat. Compd.
35
,
330
354
(
2015
).
37.
Priority Pollutant List, 2014. U.S. Environmental Protection Agency. https://www.epa.gov/sites/production/files/2015-09/documents/priority-pollutant-list-epa.pdf (accessed September 2, 2020).
38.
J. G. M.
VanRooij
,
J. H. C.
De Roos
,
M. M.
Bodelier-Bade
, and
F. J.
Jongeneelen
, “
Absorption of polycyclic aromatic hydrocarbons through human skin: Differences between anatomical sites and individuals
,”
J. Toxicol. Environ. Health
38
,
355
368
(
1993
).
39.
J. G.
VanRooij
,
M. M.
Bodelier-Bade
, and
F. J.
Jongeneelen
, “
Estimation of individual dermal and respiratory uptake of polycyclic aromatic hydrocarbons in 12 coke oven workers
,”
Br. J. Ind. Med.
50
,
623
632
(
1993
).
40.
K. W.
Fent
,
J.
Eisenberg
,
J.
Snawder
,
D.
Sammons
,
J. D.
Pleil
,
M. A.
Stiegel
,
C.
Mueller
,
G. P.
Horn
, and
J.
Dalton
, “
Systemic exposure to PAHs and benzene in firefighters suppressing controlled structure fires
,”
Ann. Occup. Hyg.
58
,
830
845
(
2014
).
41.
R. D.
Daniels
,
T. L.
Kubale
,
J. H.
Yiin
,
M. M.
Dahm
,
T. R.
Hales
,
D.
Baris
,
S. H.
Zahm
,
J. J.
Beaumont
,
K. M.
Waters
, and
L. E.
Pinkerton
, “
Mortality and cancer incidence in a pooled cohort of US firefighters from San Francisco, Chicago and Philadelphia (1950–2009)
,”
Occup. Environ. Med.
71
,
388
397
(
2014
).
42.
D. C.
Glass
,
A.
Del Monaco
,
S.
Pircher
,
S.
Vander Hoorn
, and
M. R.
Sim
, “
Mortality and cancer incidence at a fire training college
,”
Occup. Med.
66
,
536
542
(
2016
).
43.
R. J.
Tsai
,
S. E.
Luckhaupt
,
P.
Schumacher
,
R. D.
Cress
,
D. M.
Deapen
, and
G. M.
Calvert
, “
Risk of cancer among firefighters in California, 1988–2007
,”
Am. J. Ind. Med.
58
,
715
729
(
2015
).
44.
D. J.
Lee
,
T.
Koru-Sengul
,
M. N.
Hernandez
,
A. J.
Caban-Martinez
,
L. A.
McClure
,
J. A.
Mackinnon
, and
E. N.
Kobetz
, “
Cancer risk among career male and female Florida firefighters: Evidence from the Florida Firefighter Cancer Registry (1981–2014)
,”
Am. J. Ind. Med.
63
,
285
299
(
2020
).
45.
K. W.
Fent
,
J.
Eisenberg
,
D.
Evans
,
D.
Sammons
,
S.
Robertson
,
C.
Striley
,
J.
Snawder
,
C.
Mueller
,
V.
Kochenderfer
,
J.
Pleil
, and
M.
Stiegel
, “
NIOSH HHE—Evaluation of dermal exposure to polycyclic aromatic hydrocarbons in fire fighters
,” Technical Report No. 2010-0156-3196,
2013
.
46.
E.
Dybing
,
P. E.
Schwarze
,
P.
Nafstad
,
K.
Victorin
, and
T. M.
Penning
, “
Polycyclic aromatic hydrocarbons in ambient air and cancer
,” in
Air Pollution and Cancer
, IARC Scientific Publication No. 161, edited by
K.
Straif
,
A.
Cohen
, and
J.
Samet
(
International Agency for Research on Cancer
,
2013
), pp.
75
94
.
47.
IARC monographs on the evaluation of carcinogenic risks to humans. Volume 92: Some nonheterocyclic polycyclic aromatic hydrocarbons and some related exposures; IARC, 2010; Chapters 3-5, pp. 244-771.
48.
IARC Monographs on the Identification of Carcinogenic Hazards to Humans. International Agency for Research on Cancer. https://monographs.iarc.who.int/list-of-classifications (accessed September 2, 2020).
49.
A. D.
MacKerell
and
N. K.
Banavali
, “
All-atom empirical force field for nucleic acids: II. Application to molecular dynamics simulations of DNA and RNA in solution
,”
J. Comput. Chem.
21
,
105
120
(
2000
).
50.
N.
Foloppe
and
A. D.
MacKerell
, Jr.
, “
All-atom empirical force field for nucleic acids: I. Parameter optimization based on small molecule and condensed phase macromolecular target data
,”
J. Comput. Chem.
21
,
86
104
(
2000
).
51.
H. J. C.
Yeh
,
J. M.
Sayer
,
X.
Liu
,
A. S.
Altieri
,
R. A.
Byrd
,
M. K.
Lakshman
,
H.
Yagi
,
E. J.
Schurter
,
D. G.
Gorenstein
, and
D. M.
Jerina
, “
NMR solution structure of a nonanucleotide duplex with a dG mismatch opposite a 10S adduct derived from trans addition of a deoxyadenosine N6-amino group to (+)-(7R,8S,9S,10R)-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo [a] pyrene: An unusual syn glycosidic torsion angle at the modified dA
,”
Biochemistry
34
,
13570
13581
(
1995
).
52.
W.
Humphrey
,
A.
Dalke
, and
K.
Schulten
, “
VMD: Visual molecular dynamics
,”
J. Mol. Graphics
14
,
33
38
(
1996
).
53.
M. J.
Frisch
,
G. W.
Trucks
,
H. B.
Schlegel
,
G. E.
Scuseria
,
M. A.
Robb
,
J. R.
Cheeseman
,
G.
Scalmani
,
V.
Barone
,
G. A.
Petersson
,
H.
Nakatsuji
,
X.
Li
,
M.
Caricato
,
A. V.
Marenich
,
J.
Bloino
,
B. G.
Janesko
,
R.
Gomperts
,
B.
Mennucci
,
H. P.
Hratchian
,
J. V.
Ortiz
,
A. F.
Izmaylov
,
J. L.
Sonnenberg
,
D.
Williams-Young
,
F.
Ding
,
F.
Lipparini
,
F.
Egidi
,
J.
Goings
,
B.
Peng
,
A.
Petrone
,
T.
Henderson
,
D.
Ranasinghe
,
V. G.
Zakrzewski
,
J.
Gao
,
N.
Rega
,
G.
Zheng
,
W.
Liang
,
M.
Hada
,
M.
Ehara
,
K.
Toyota
,
R.
Fukuda
,
J.
Hasegawa
,
M.
Ishida
,
T.
Nakajima
,
Y.
Honda
,
O.
Kitao
,
H.
Nakai
,
T.
Vreven
,
K.
Throssell
,
J. A.
Montgomery
, Jr.
,
J. E.
Peralta
,
F.
Ogliaro
,
M. J.
Bearpark
,
J. J.
Heyd
,
E. N.
Brothers
,
K. N.
Kudin
,
V. N.
Staroverov
,
T. A.
Keith
,
R.
Kobayashi
,
J.
Normand
,
K.
Raghavachari
,
A. P.
Rendell
,
J. C.
Burant
,
S. S.
Iyengar
,
J.
Tomasi
,
M.
Cossi
,
J. M.
Millam
,
M.
Klene
,
C.
Adamo
,
R.
Cammi
,
J. W.
Ochterski
,
R. L.
Martin
,
K.
Morokuma
,
O.
Farkas
,
J. B.
Foresman
, and
D. J.
Fox
, Gaussian, Revision C.01,
Gaussian, Inc.
,
Wallingford, CT
,
2016
.
54.
J. C.
Phillips
,
R.
Braun
,
W.
Wang
,
J.
Gumbart
,
E.
Tajkhorshid
,
E.
Villa
,
C.
Chipot
,
R. D.
Skeel
,
L.
Kalé
, and
K.
Schulten
, “
Scalable molecular dynamics with NAMD
,”
J. Comput. Chem.
26
,
1781
1802
(
2005
).
55.
K.
Vanommeslaeghe
, CGenFF FAQs http://mackerell.umaryland.edu/∼kenno/cgenff/faq.php (accessed September 2, 2020).
56.
D. J.
Urwin
and
A. N.
Alexandrova
, “
Dataset for: Regularization of least squares problems in CHARMM parameter optimization by truncated singular value decompositions
,”
2021
; https://github.com/ derekjurwin/PAH-DNA-TSVD.
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