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Jafari S, Ryde U, Irani M. Two local minima for structures of [4Fe-4S] clusters obtained with density functional theory methods. Sci Rep 2023; 13:10832. [PMID: 37402767 PMCID: PMC10319735 DOI: 10.1038/s41598-023-37755-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 06/27/2023] [Indexed: 07/06/2023] Open
Abstract
[4Fe-4S] clusters are essential cofactors in many proteins involved in biological redox-active processes. Density functional theory (DFT) methods are widely used to study these clusters. Previous investigations have indicated that there exist two local minima for these clusters in proteins. We perform a detailed study of these minima in five proteins and two oxidation states, using combined quantum mechanical and molecular mechanical (QM/MM) methods. We show that one local minimum (L state) has longer Fe-Fe distances than the other (S state), and that the L state is more stable for all cases studied. We also show that some DFT methods may only obtain the L state, while others may obtain both states. Our work provides new insights into the structural diversity and stability of [4Fe-4S] clusters in proteins, and highlights the importance of reliable DFT methods and geometry optimization. We recommend r2SCAN for optimizing [4Fe-4S] clusters in proteins, which gives the most accurate structures for the five proteins studied.
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Affiliation(s)
- Sonia Jafari
- Department of Chemistry, University of Kurdistan, P.O.Box 66175-416, Sanandaj, Iran
| | - Ulf Ryde
- Department of Theoretical Chemistry, Lund University, P.O.Box 124, 221 00, Lund, Sweden
| | - Mehdi Irani
- Department of Chemistry, University of Kurdistan, P.O.Box 66175-416, Sanandaj, Iran.
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2
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Quantum Mechanical Calculations of Redox Potentials of the Metal Clusters in Nitrogenase. MOLECULES (BASEL, SWITZERLAND) 2022; 28:molecules28010065. [PMID: 36615260 PMCID: PMC9822455 DOI: 10.3390/molecules28010065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 12/14/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
We have calculated redox potentials of the two metal clusters in Mo-nitrogenase with quantum mechanical (QM) calculations. We employ an approach calibrated for iron-sulfur clusters with 1-4 Fe ions, involving QM-cluster calculations in continuum solvent and large QM systems (400-500 atoms), based on structures from combined QM and molecular mechanics (QM/MM) geometry optimisations. Calculations on the P-cluster show that we can reproduce the experimental redox potentials within 0.33 V. This is similar to the accuracy obtained for the smaller clusters, although two of the redox reactions involve also proton transfer. The calculated P1+/PN redox potential is nearly the same independently of whether P1+ is protonated or deprotonated, explaining why redox titrations do not show any pH dependence. For the FeMo cluster, the calculations clearly show that the formal oxidation state of the cluster in the resting E0 state is MoIIIFe3IIFe4III , in agreement with previous experimental studies and QM calculations. Moreover, the redox potentials of the first five E0-E4 states are nearly constant, as is expected if the electrons are delivered by the same site (the P-cluster). However, the redox potentials are insensitive to the formal oxidation states of the Fe ion (i.e., whether the added protons bind to sulfide or Fe ions). Finally, we show that the later (E4-E8) states of the reaction mechanism have redox potential that are more positive (i.e., more exothermic) than that of the E0/E1 couple.
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Jafari S, Tavares Santos YA, Bergmann J, Irani M, Ryde U. Benchmark Study of Redox Potential Calculations for Iron-Sulfur Clusters in Proteins. Inorg Chem 2022; 61:5991-6007. [PMID: 35403427 PMCID: PMC9044450 DOI: 10.1021/acs.inorgchem.1c03422] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Redox potentials
have been calculated for 12 different iron–sulfur
sites of 6 different types with 1–4 iron ions. Structures were
optimized with combined quantum mechanical and molecular mechanical
(QM/MM) methods, and the redox potentials were calculated using the
QM/MM energies, single-point QM methods in a continuum solvent or
by QM/MM thermodynamic cycle perturbations. We show that the best
results are obtained with a large QM system (∼300 atoms, but
a smaller QM system, ∼150 atoms, can be used for the QM/MM
geometry optimization) and a large value of the dielectric constant
(80). For absolute redox potentials, the B3LYP density functional
method gives better results than TPSS, and the results are improved
with a larger basis set. However, for relative redox potentials, the
opposite is true. The results are insensitive to the force field (charges
of the surroundings) used for the QM/MM calculations or whether the
protein and solvent outside the QM system are relaxed or kept fixed
at the crystal structure. With the best approach for relative potentials,
mean absolute and maximum deviations of 0.17 and 0.44 V, respectively,
are obtained after removing a systematic error of −0.55 V.
Such an approach can be used to identify the correct oxidation states
involved in a certain redox reaction. We
have studied redox potentials of 12 iron−sulfur
sites of 6 types with 1−4 iron ions. Structures were optimized
with combined quantum mechanical and molecular mechanical (QM/MM)
methods, and the redox potentials were calculated with QM/MM, QM calculations
in a continuum solvent or by QM/MM thermodynamic cycle perturbations.
The best results are obtained with the second approach using ∼300
atoms in the QM model and a large dielectric constant.
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Affiliation(s)
- Sonia Jafari
- Department of Chemistry, University of Kurdistan, 66175-416 Sanandaj, Iran.,Department of Theoretical Chemistry, Chemical Centre, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Yakini A Tavares Santos
- Department of Theoretical Chemistry, Chemical Centre, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Justin Bergmann
- Department of Theoretical Chemistry, Chemical Centre, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
| | - Mehdi Irani
- Department of Chemistry, University of Kurdistan, 66175-416 Sanandaj, Iran
| | - Ulf Ryde
- Department of Theoretical Chemistry, Chemical Centre, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Li B, Steindel P, Haddad N, Elliott SJ. Maximizing (Electro)catalytic CO 2 Reduction with a Ferredoxin-Based Reduction Potential Gradient. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00092] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Bin Li
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Phillip Steindel
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Narmien Haddad
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | - Sean J. Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts 02215, United States
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Tambi R, Bayoumi R, Lansberg P, Banerjee Y. Blending Gagne's Instructional Model with Peyton's Approach to Design an Introductory Bioinformatics Lesson Plan for Medical Students: Proof-of-Concept Study. JMIR MEDICAL EDUCATION 2018; 4:e11122. [PMID: 30361192 PMCID: PMC6231819 DOI: 10.2196/11122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 05/25/2023]
Abstract
BACKGROUND With the rapid integration of genetics into medicine, it has become evident that practicing physicians as well as medical students and clinical researchers need to be updated on the fundamentals of bioinformatics. To achieve this, the following gaps need to be addressed: a lack of defined learning objectives for "Bioinformatics for Medical Practitioner" courses, an absence of a structured lesson plan to disseminate the learning objectives, and no defined step-by-step strategy to teach the essentials of bioinformatics in the medical curriculum. OBJECTIVE The objective of this study was to address these gaps to design a streamlined pedagogical strategy for teaching basics of bioinformatics in the undergraduate medical curriculum. METHODS The established instructional design strategies employed in medical education-Gagne's 9 events of instruction-were followed with further contributions from Peyton's four-step approach to design a structured lesson plan in bioinformatics. RESULTS First, we defined the specifics of bioinformatics that a medical student or health care professional should be introduced to use this knowledge in a clinical context. Second, we designed a structured lesson plan using a blended approach from both Gagne's and Peyton's instructional models. Lastly, we delineated a step-by-step strategy employing free Web-based bioinformatics module, combining it with a clinical scenario of familial hypercholesterolemia to disseminate the defined specifics of bioinformatics. Implementation of Schon's reflective practice model indicated that the activity was stimulating for the students with favorable outcomes regarding their basic training in bioinformatics. CONCLUSIONS To the best of our knowledge, the present lesson plan is the first that outlines an effective dissemination strategy for integrating introductory bioinformatics into a medical curriculum. Further, the lesson plan blueprint can be used to develop similar skills in workshops, continuing professional development, or continuing medical education events to introduce bioinformatics to practicing physicians.
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Affiliation(s)
- Richa Tambi
- Department of Basic Medical Sciences, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Riad Bayoumi
- Department of Basic Medical Sciences, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
| | - Peter Lansberg
- Department of Pediatrics, University Medical Center Groningen, Groningen, Netherlands
| | - Yajnavalka Banerjee
- Department of Basic Medical Sciences, Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai, United Arab Emirates
- University of Dundee, Department of Medical Education, University of Dundee, Dundee, United Kingdom
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Atkinson JT, Campbell I, Bennett GN, Silberg JJ. Cellular Assays for Ferredoxins: A Strategy for Understanding Electron Flow through Protein Carriers That Link Metabolic Pathways. Biochemistry 2016; 55:7047-7064. [DOI: 10.1021/acs.biochem.6b00831] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua T. Atkinson
- Systems,
Synthetic, and Physical Biology Graduate Program, Rice University, MS-180, 6100 Main Street, Houston, Texas 77005, United States
| | - Ian Campbell
- Biochemistry
and Cell Biology Graduate Program, Rice University, MS-140, 6100
Main Street, Houston, Texas 77005, United States
| | - George N. Bennett
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Chemical and Biomolecular Engineering, Rice University, MS-362,
6100 Main Street, Houston, Texas 77005, United States
| | - Jonathan J. Silberg
- Department
of Biosciences, Rice University, MS-140, 6100 Main Street, Houston, Texas 77005, United States
- Department
of Bioengineering, Rice University, MS-142, 6100 Main Street, Houston, Texas 77005, United States
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Konc J, Miller BT, Štular T, Lešnik S, Woodcock HL, Brooks BR, Janežič D. ProBiS-CHARMMing: Web Interface for Prediction and Optimization of Ligands in Protein Binding Sites. J Chem Inf Model 2015; 55:2308-14. [DOI: 10.1021/acs.jcim.5b00534] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Janez Konc
- Laboratory
for Molecular Modeling, National Institute of Chemistry, Hajdrihova
19, SI-1000, Ljubljana, Slovenia
- Faculty
of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI-6000, Koper, Slovenia
| | - Benjamin T. Miller
- Laboratory
of Computational Biology, Biochemistry and Biophysics Center, National
Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Tanja Štular
- Faculty
of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI-6000, Koper, Slovenia
| | - Samo Lešnik
- Laboratory
for Molecular Modeling, National Institute of Chemistry, Hajdrihova
19, SI-1000, Ljubljana, Slovenia
| | - H. Lee Woodcock
- Department
of Chemistry, University of South Florida, 4202 East Fowler Ave., Tampa, Florida 33620, United States
| | - Bernard R. Brooks
- Laboratory
of Computational Biology, Biochemistry and Biophysics Center, National
Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Dušanka Janežič
- Faculty
of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška 8, SI-6000, Koper, Slovenia
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Pevzner Y, Frugier E, Schalk V, Caflisch A, Woodcock HL. Fragment-based docking: development of the CHARMMing Web user interface as a platform for computer-aided drug design. J Chem Inf Model 2014; 54:2612-20. [PMID: 25151852 PMCID: PMC4170817 DOI: 10.1021/ci500322k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Indexed: 01/24/2023]
Abstract
Web-based user interfaces to scientific applications are important tools that allow researchers to utilize a broad range of software packages with just an Internet connection and a browser. One such interface, CHARMMing (CHARMM interface and graphics), facilitates access to the powerful and widely used molecular software package CHARMM. CHARMMing incorporates tasks such as molecular structure analysis, dynamics, multiscale modeling, and other techniques commonly used by computational life scientists. We have extended CHARMMing's capabilities to include a fragment-based docking protocol that allows users to perform molecular docking and virtual screening calculations either directly via the CHARMMing Web server or on computing resources using the self-contained job scripts generated via the Web interface. The docking protocol was evaluated by performing a series of "re-dockings" with direct comparison to top commercial docking software. Results of this evaluation showed that CHARMMing's docking implementation is comparable to many widely used software packages and validates the use of the new CHARMM generalized force field for docking and virtual screening.
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Affiliation(s)
- Yuri Pevzner
- Department
of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, Florida 33620-5250, United States
| | - Emilie Frugier
- Department
of Biochemistry, University of Zurich, CH-8057 Zurich, Switzerland
| | - Vinushka Schalk
- Department
of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, Florida 33620-5250, United States
- Department
of Natural Sciences, New College of Florida, Sarasota, Florida 34243, United States
| | - Amedeo Caflisch
- Department
of Biochemistry, University of Zurich, CH-8057 Zurich, Switzerland
| | - H. Lee Woodcock
- Department
of Chemistry, University of South Florida, 4202 E. Fowler Ave., CHE205, Tampa, Florida 33620-5250, United States
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Affiliation(s)
- Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (QC); (RN)
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute, Frederick, Maryland, United States of America
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- * E-mail: (QC); (RN)
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