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Montemiglio LC, Gugole E, Freda I, Exertier C, D’Auria L, Chen CG, Nardi AN, Cerutti G, Parisi G, D’Abramo M, Savino C, Vallone B. Point Mutations at a Key Site Alter the Cytochrome P450 OleP Structural Dynamics. Biomolecules 2021; 12:biom12010055. [PMID: 35053203 PMCID: PMC8774231 DOI: 10.3390/biom12010055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/26/2021] [Accepted: 12/29/2021] [Indexed: 12/16/2022] Open
Abstract
Substrate binding to the cytochrome P450 OleP is coupled to a large open-to-closed transition that remodels the active site, minimizing its exposure to the external solvent. When the aglycone substrate binds, a small empty cavity is formed between the I and G helices, the BC loop, and the substrate itself, where solvent molecules accumulate mediating substrate-enzyme interactions. Herein, we analyzed the role of this cavity in substrate binding to OleP by producing three mutants (E89Y, G92W, and S240Y) to decrease its volume. The crystal structures of the OleP mutants in the closed state bound to the aglycone 6DEB showed that G92W and S240Y occupied the cavity, providing additional contact points with the substrate. Conversely, mutation E89Y induces a flipped-out conformation of this amino acid side chain, that points towards the bulk, increasing the empty volume. Equilibrium titrations and molecular dynamic simulations indicate that the presence of a bulky residue within the cavity impacts the binding properties of the enzyme, perturbing the conformational space explored by the complexes. Our data highlight the relevance of this region in OleP substrate binding and suggest that it represents a key substrate-protein contact site to consider in the perspective of redirecting its activity towards alternative compounds.
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Affiliation(s)
- Linda Celeste Montemiglio
- Institute of Molecular Biology and Pathology, CNR c/o Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (L.C.M.); (C.E.)
| | - Elena Gugole
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (E.G.); (I.F.); (L.D.); (G.C.)
| | - Ida Freda
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (E.G.); (I.F.); (L.D.); (G.C.)
| | - Cécile Exertier
- Institute of Molecular Biology and Pathology, CNR c/o Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (L.C.M.); (C.E.)
| | - Lucia D’Auria
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (E.G.); (I.F.); (L.D.); (G.C.)
| | - Cheng Giuseppe Chen
- Department of Chemistry, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (C.G.C.); (A.N.N.); (M.D.)
| | - Alessandro Nicola Nardi
- Department of Chemistry, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (C.G.C.); (A.N.N.); (M.D.)
| | - Gabriele Cerutti
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (E.G.); (I.F.); (L.D.); (G.C.)
| | - Giacomo Parisi
- Center for Life Nano & Neuro-Science, Fondazione Istituto Italiano di Tecnologia, IIT, 00185 Rome, Italy;
| | - Marco D’Abramo
- Department of Chemistry, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (C.G.C.); (A.N.N.); (M.D.)
| | - Carmelinda Savino
- Institute of Molecular Biology and Pathology, CNR c/o Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (L.C.M.); (C.E.)
- Correspondence: (C.S.); (B.V.); Tel.: +39-06-49910548 (C.S. & B.V.)
| | - Beatrice Vallone
- Department of Biochemical Sciences “A. Rossi Fanelli”, University of Rome, Sapienza, P.le A. Moro 5, 00185 Rome, Italy; (E.G.); (I.F.); (L.D.); (G.C.)
- Correspondence: (C.S.); (B.V.); Tel.: +39-06-49910548 (C.S. & B.V.)
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Balasco N, Alba J, D'Abramo M, Vitagliano L. Quaternary Structure Transitions of Human Hemoglobin: An Atomic-Level View of the Functional Intermediate States. J Chem Inf Model 2021; 61:3988-3999. [PMID: 34375114 PMCID: PMC9473481 DOI: 10.1021/acs.jcim.1c00315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Human hemoglobin (HbA) is one of the prototypal systems used to investigate structure-function relationships in proteins. Indeed, HbA has been used to develop the basic concepts of protein allostery, although the atomic-level mechanism underlying the HbA functionality is still highly debated. This is due to the fact that most of the three-dimensional structural information collected over the decades refers to the endpoints of HbA functional transition with little data available for the intermediate states. Here, we report molecular dynamics (MD) simulations by focusing on the relevance of the intermediate states of the protein functional transition unraveled by the crystallographic studies carried out on vertebrate Hbs. Fully atomistic simulations of the HbA T-state indicate that the protein undergoes a spontaneous transition toward the R-state. The inspection of the trajectory structures indicates that the protein significantly populates the intermediate HL-(C) state previously unraveled by crystallography. In the structural transition, it also assumes the intermediate states crystallographically detected in Antarctic fish Hbs. This finding suggests that HbA and Antarctic fish Hbs, in addition to the endpoints of the transitions, also share a similar deoxygenation pathway despite a distace of hundreds of millions of years in the evolution scale. Finally, using the essential dynamic sampling methodology, we gained some insights into the reverse R to T transition that is not spontaneously observed in classic MD simulations.
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Affiliation(s)
- Nicole Balasco
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134 Naples, Italy
| | - Josephine Alba
- Department of Chemistry, University of Rome Sapienza, P.le A.Moro 5, 00185 Rome, Italy
| | - Marco D'Abramo
- Department of Chemistry, University of Rome Sapienza, P.le A.Moro 5, 00185 Rome, Italy
| | - Luigi Vitagliano
- Institute of Biostructures and Bioimaging, CNR, Via Mezzocannone 16, 80134 Naples, Italy
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Wu H, Huang H, Post CB. All-atom adaptively biased path optimization of Src kinase conformational inactivation: Switched electrostatic network in the concerted motion of αC helix and the activation loop. J Chem Phys 2020; 153:175101. [PMID: 33167630 DOI: 10.1063/5.0021603] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
A method to optimize a conformational pathway through a space of well-chosen reduced variables is employed to advance our understanding of protein conformational equilibrium. The adaptively biased path optimization strategy utilizes unrestricted, enhanced sampling in the region of a path in the reduced-variable space to identify a broad path between two stable end-states. Application to the inactivation transition of the Src tyrosine kinase catalytic domain reveals new insight into this well studied conformational equilibrium. The mechanistic description gained from identifying the motions and structural features along the path includes details of the switched electrostatic network found to underpin the transition. The free energy barrier along the path results from rotation of a helix, αC, that is tightly correlated with motions in the activation loop (A-loop) as well as distal regions in the C-lobe. Path profiles of the reduced variables clearly demonstrate the strongly correlated motions. The exchange of electrostatic interactions among residues in the network is key to these interdependent motions. In addition, the increased resolution from an all-atom model in defining the path shows multiple components for the A-loop motion and that different parts of the A-loop contribute throughout the length of the path.
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Affiliation(s)
- Heng Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, Markey Center for Structural Biology, Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, USA
| | - He Huang
- Department of Medicinal Chemistry and Molecular Pharmacology, Markey Center for Structural Biology, Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, USA
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Markey Center for Structural Biology, Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana 47907, USA
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Di Rienzo L, Milanetti E, Alba J, D'Abramo M. Quantitative Characterization of Binding Pockets and Binding Complementarity by Means of Zernike Descriptors. J Chem Inf Model 2020; 60:1390-1398. [PMID: 32050068 PMCID: PMC7997106 DOI: 10.1021/acs.jcim.9b01066] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, we describe the application of the Zernike formalism to quantitatively characterize the binding pockets of two sets of biologically relevant systems. Such an approach, when applied to molecular dynamics trajectories, is able to pinpoint the subtle differences between very similar molecular regions and their impact on the local propensity to ligand binding, allowing us to quantify such differences. The statistical robustness of our procedure suggests that it is very suitable to describe protein binding sites and protein-ligand interactions within a rigorous and well-defined framework.
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Affiliation(s)
- Lorenzo Di Rienzo
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Edoardo Milanetti
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy.,Center for Life Nano Science@Sapienza, Italian Institute of Technology, Viale Regina Elena 291, 00161 Rome, Italy
| | - Josephine Alba
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
| | - Marco D'Abramo
- Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro, 5, 00185 Rome, Italy
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