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Sala D, Musiani F, Rosato A. Application of Molecular Dynamics to the Investigation of Metalloproteins Involved in Metal Homeostasis. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800602] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Davide Sala
- Magnetic Resonance Center (CERM); University of Florence; Via Luigi Sacconi 6 50019 Sesto Fiorentino Italy
| | - Francesco Musiani
- Laboratory of Bioinorganic Chemistry; Department of Pharmacy and Biotechnology; University of Bologna; Viale Giuseppe Fanin 40, I 40127 Bologna Italy
| | - Antonio Rosato
- Magnetic Resonance Center (CERM); University of Florence; Via Luigi Sacconi 6 50019 Sesto Fiorentino Italy
- Consorzio Interuniversitario di Risonanze Magnetiche di Metallo Proteine; Via Luigi Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
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Mushtaq AU, Park JS, Bae SH, Kim HY, Yeo KJ, Hwang E, Lee KY, Jee JG, Cheong HK, Jeon YH. Ligand-Mediated Folding of the OmpA Periplasmic Domain from Acinetobacter baumannii. Biophys J 2017; 112:2089-2098. [PMID: 28538146 DOI: 10.1016/j.bpj.2017.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/10/2017] [Accepted: 04/13/2017] [Indexed: 11/27/2022] Open
Abstract
The periplasmic domain of OmpA from Acinetobacter baumannii (AbOmpA-PD) binds to diaminopimelate and anchors the outer membrane to the peptidoglycan layer in the cell wall. Although the crystal structure of AbOmpA-PD with its ligands has been reported, the mechanism of ligand-mediated folding of AbOmpA remains elusive. Here, we report that in vitro refolded apo-AbOmpA-PD in the absence of ligand exists as a mixture of two partially folded forms in solution: mostly unfolded (apo-state I) and hololike (apo-state II) states. Binding of the diaminopimelate or glycine ligand induced complete folding of AbOmpA-PD. The apo-state I was highly flexible and contained some secondary structural elements, whereas the apo-state II closely resembled the holo-state in terms of both structure and backbone dynamics, except for the ligand-binding region. 15N-relaxation-dispersion analyses for apo-state II revealed substantial motion on a millisecond timescale of residues in the H3 helix near the ligand-binding site, with this motion disappearing upon ligand binding. These results provide an insight into the ligand-mediated folding mechanism of AbOmpA-PD in solution.
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Affiliation(s)
- Ameeq Ul Mushtaq
- College of Pharmacy, Korea University, Sejong-ro, Sejong, Republic of Korea
| | - Jeong Soon Park
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea; CKD Research Institute, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea; College of Pharmacy, Kyungpook National University, Buk-gu, Daegu, Republic of Korea
| | - Sung-Hun Bae
- CKD Research Institute, Giheung-gu, Yongin-si, Gyeonggi-do, Republic of Korea
| | - Hye-Yeon Kim
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea; Center for Convergent Research of Emerging Virus Infection, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Kwon Joo Yeo
- College of Pharmacy, Korea University, Sejong-ro, Sejong, Republic of Korea; Division of Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea
| | - Eunha Hwang
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea
| | - Ki Yong Lee
- College of Pharmacy, Korea University, Sejong-ro, Sejong, Republic of Korea
| | - Jun-Goo Jee
- College of Pharmacy, Kyungpook National University, Buk-gu, Daegu, Republic of Korea
| | - Hae-Kap Cheong
- Division of Bioconvergence Analysis, Korea Basic Science Institute, Ochang, Chungbuk, Republic of Korea.
| | - Young Ho Jeon
- College of Pharmacy, Korea University, Sejong-ro, Sejong, Republic of Korea.
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Tripet BP, Goel A, Copie V. Internal dynamics of the tryptophan repressor (TrpR) and two functionally distinct TrpR variants, L75F-TrpR and A77V-TrpR, in their l-Trp-bound forms. Biochemistry 2011; 50:5140-53. [PMID: 21553830 DOI: 10.1021/bi200389k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Backbone amide dynamics of the Escherichia coli tryptophan repressor protein (WT-TrpR) and two functionally distinct variants, L75F-TrpR and A77V-TrpR, in their holo (l-tryptophan corepressor-bound) form have been characterized using (15)N nuclear magnetic resonance (NMR) relaxation. The three proteins possess very similar structures, ruling out major conformational differences as the source of their functional differences, and suggest that changes in protein flexibility are at the origin of their distinct functional properties. Comparison of site specific (15)N-T(1), (15)N-T(2), (15)N-{(1)H} nuclear Overhauser effect, reduced spectral density, and generalized order (S(2)) parameters indicates that backbone dynamics in the three holo-repressors are overall very similar with a few notable and significant exceptions for backbone atoms residing within the proteins' DNA-binding domain. We find that flexibility is highly restricted for amides in core α-helices (i.e., helices A-C and F), and a comparable "stiffening" is observed for residues in the DNA recognition helix (helix E) of the helix D-turn-helix E (HTH) DNA-binding domain of the three holo-repressors. Unexpectedly, amides located in helix D and in adjacent turn regions remain flexible. These data support the concept that residual flexibility in TrpR is essential for repressor function, DNA binding, and molecular recognition of target operators. Comparison of the (15)N NMR relaxation parameters of the holo-TrpRs with those of the apo-TrpRs indicates that the single-point amino acid substitutions, L75F and A77V, perturb the flexibility of backbone amides of TrpR in very different ways and are most pronounced in the apo forms of the three repressors. Finally, we present these findings in the context of other DNA-binding proteins and the role of protein flexibility in molecular recognition.
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Affiliation(s)
- Brian P Tripet
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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HMGB1–Carbenoxolone Interactions: Dynamics Insights from Combined Nuclear Magnetic Resonance and Molecular Dynamics. Chem Asian J 2011; 6:1171-80. [DOI: 10.1002/asia.201000726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Indexed: 11/07/2022]
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Goel A, Tripet BP, Tyler RC, Nebert LD, Copié V. Backbone amide dynamics studies of Apo-L75F-TrpR, a temperature-sensitive mutant of the tryptophan repressor protein (TrpR): comparison with the (15)N NMR relaxation profiles of wild-type and A77V mutant Apo-TrpR repressors. Biochemistry 2010; 49:8006-19. [PMID: 20718459 DOI: 10.1021/bi100508u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Backbone amide dynamics studies were conducted on a temperature-sensitive mutant (L75F-TrpR) of the tryptophan repressor protein (TrpR) of Escherichia coli in its apo (i.e., no l-tryptophan corepressor-bound) form. The (15)N NMR relaxation profiles of apo-L75F-TrpR were analyzed and compared to those of wild-type (WT) and super-repressor mutant (A77V) TrpR proteins, also in their apo forms. The (15)N NMR relaxation data ((15)N-T(1), (15)N-T(2), and heteronuclear (15)N-{(1)H}-nOe) recorded on all three aporepressors at a magnetic field strength of 600 MHz ((1)H Larmor frequency) were analyzed to extract dynamics parameters, including diffusion tensor ratios (D(∥)/D(⊥)), correlation times (τ(m)) for overall reorientations of the proteins in solution, reduced spectral density terms [J(eff)(0), J(0.87ω(H)), J(ω(N))], and generalized order parameters (S(2)), which report on protein internal motions on the picosecond to nanosecond and slower microsecond to millisecond chemical exchange time scales. Our results indicate that all three aporepressors exhibit comparable D(∥)/D(⊥) ratios and characteristic time constants, τ(m), for overall global reorientation, indicating that in solution, all three apoproteins display very similar overall shape, structure, and rotational diffusion properties. Comparison of (15)N NMR relaxation data, reduced spectral density profiles, and generalized S(2) order parameters indicated that these parameters are quite uniform for backbone amides positioned within the four (A-C and F) core α-helices of all three aporepressors. In contrast, small but noticeable differences in internal dynamics were observed for backbone amides located within the helix D-turn-helix E DNA-binding domain of the apo-TrpR proteins. The significance of these dynamics differences in terms of the biophysical characteristics and ligand binding properties of the three apo-TrpR proteins is discussed.
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Affiliation(s)
- Anupam Goel
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
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Farina B, Pirone L, Russo L, Viparelli F, Doti N, Pedone C, Pedone EM, Fattorusso R. NMR backbone dynamics studies of human PED/PEA-15 outline protein functional sites. FEBS J 2010; 277:4229-40. [PMID: 20825483 DOI: 10.1111/j.1742-4658.2010.07812.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PED/PEA-15 (phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes) is a ubiquitously expressed protein and a key regulator of cell growth and glucose metabolism. PED/PEA-15 mediates both homotypic and heterotypic interactions and is constituted by an N-terminal canonical death effector domain and a C-terminal tail. In the present study, the backbone dynamics of PED/PEA-15 via (15)N R(1) and R(2) and steady-state [(1)H]-(15)N NOE measurements is reported. The dynamic parameters were analyzed using both Lipari-Szabo model-free formalism and a reduced spectral density mapping approach. The results obtained define a polar and charged surface of the death effector domain characterized by internal motions in the micro- to millisecond timescale, which is crucial for the multiple heterotypic functional protein-protein interactions in which PED/PEA-15 is involved. The present study contributes to a better understanding of the molecular basis of the PED/PEA-15 functional interactions and provides a more detailed surface for the design and development of PED/PEA-15 binders.
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Kaieda S, Matsui C, Mimori-Kiyosue Y, Ikegami T. Structural basis of the recognition of the SAMP motif of adenomatous polyposis coli by the Src-homology 3 domain. Biochemistry 2010; 49:5143-53. [PMID: 20509626 DOI: 10.1021/bi100563z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Elucidation of the basis of interactions between biological molecules is essential for the understanding of living systems. Src-homology 3 (SH3) domains play critical roles in interaction networks of proteins by recognizing a proline-rich sequence motif, PxxP. There are, however, several SH3 domains that specifically bind to polypeptide chains without the conventional recognition sequence. The SH3 domain of DDEF1 associates with the SAMP motifs of the adenomatous polyposis coli (APC) tumor suppressor. The SAMP motifs are indispensable for the normal function of APC in tumor suppression. Here we present the structural basis of the interaction between the DDEF1-SH3 domain and the APC-SAMP motifs. We determined the solution structures of the DDEF1-SH3 domain both in a free state and in a complex with APC-SAMP. As the affinity of the interaction was not sufficiently high for the determination of the complex structure in solution by conventional methods, we utilized a fusion protein of the DDEF1-SH3 domain and APC-SAMP. The structures revealed that the SAMP motif adopts a class II polyproline type II helix even though it does not contain the PxxP motif and that a characteristically large hydrophobic pocket of the SH3 domain confers high selectivity to the interaction. Furthermore, investigation into the backbone dynamics of the free and bound systems by NMR spin relaxation experiments demonstrated that the DDEF1-SH3 domain exhibits high flexibility at the peptide recognition site in the absence of the ligand and that most residues of the APC-SAMP motif display extensive local motions even in the stable complex.
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Affiliation(s)
- Shuji Kaieda
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Ishida H, Rainaldi M, Vogel HJ. Structural studies of soybean calmodulin isoform 4 bound to the calmodulin-binding domain of tobacco mitogen-activated protein kinase phosphatase-1 provide insights into a sequential target binding mode. J Biol Chem 2009; 284:28292-28305. [PMID: 19667066 PMCID: PMC2788880 DOI: 10.1074/jbc.m109.025080] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2009] [Revised: 07/10/2009] [Indexed: 01/22/2023] Open
Abstract
The calcium regulatory protein calmodulin (CaM) binds in a calcium-dependent manner to numerous target proteins. The calmodulin-binding domain (CaMBD) region of Nicotiana tabacum MAPK phosphatase has an amino acid sequence that does not resemble the CaMBD of any other known Ca(2+)-CaM-binding proteins. Using a unique fusion protein strategy, we have been able to obtain a high resolution solution structure of the complex of soybean Ca(2+)-CaM4 (SCaM4) and this CaMBD. Complete isotope labeling of both parts of the complex in the fusion protein greatly facilitated the structure determination by NMR. The 12-residue CaMBD region was found to bind exclusively to the C-lobe of SCaM4. A specific Trp and Leu side chain are utilized to facilitate strong binding through a novel "double anchor" motif. Moreover, the orientation of the helical peptide on the surface of Ca(2+)-SCaM4 is distinct from other known complexes. The N-lobe of Ca(2+)-SCaM4 in the complex remains free for additional interactions and could possibly act as a calcium-dependent adapter protein. Signaling through the MAPK pathway and increases in intracellular Ca(2+) are both hallmarks of the plant stress response, and our data support the notion that coordination of these responses may occur through the formation of a unique CaM-MAPK phosphatase multiprotein complex.
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Affiliation(s)
- Hiroaki Ishida
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Mario Rainaldi
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada
| | - Hans J Vogel
- Department of Biological Sciences, University of Calgary, Calgary, Alberta T2N 1N4, Canada.
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Spontaneous conformational change and toxin binding in alpha7 acetylcholine receptor: insight into channel activation and inhibition. Proc Natl Acad Sci U S A 2008; 105:8280-5. [PMID: 18541920 DOI: 10.1073/pnas.0710530105] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Nicotinic AChRs (nAChRs) represent a paradigm for ligand-gated ion channels. Despite intensive studies over many years, our understanding of the mechanisms of activation and inhibition for nAChRs is still incomplete. Here, we present molecular dynamics (MD) simulations of the alpha7 nAChR ligand-binding domain, both in apo form and in alpha-Cobratoxin-bound form, starting from the respective homology models built on crystal structures of the acetylcholine-binding protein. The toxin-bound form was relatively stable, and its structure was validated by calculating mutational effects on the toxin-binding affinity. However, in the apo form, one subunit spontaneously moved away from the conformation of the other four subunits. This motion resembles what has been proposed for leading to channel opening. At the top, the C loop and the adjacent beta7-beta8 loop swing downward and inward, whereas at the bottom, the F loop and the C terminus of beta10 swing in the opposite direction. These swings appear to tilt the whole subunit clockwise. The resulting changes in solvent accessibility show strong correlation with experimental results by the substituted cysteine accessibility method upon addition of acetylcholine. Our MD simulation results suggest a mechanistic model in which the apo form, although predominantly sampling the "closed" state, can make excursions into the "open" state. The open state has high affinity for agonists, leading to channel activation, whereas the closed state upon distortion has high affinity for antagonists, leading to inhibition.
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Lee HJ, Yoon YJ, Jang DS, Kim C, Cha HJ, Hong BH, Choi KY, Lee HC. 15N NMR Relaxation Studies of Y14F Mutant of Ketosteroid Isomerase: The Influence of Mutation on Backbone Mobility. ACTA ACUST UNITED AC 2008; 144:159-66. [DOI: 10.1093/jb/mvn053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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