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Liebau J, Laatsch BF, Rusnak J, Gunderson K, Finke B, Bargender K, Narkiewicz-Jodko A, Weeks K, Williams MT, Shulgina I, Musier-Forsyth K, Bhattacharyya S, Hati S. Polyethylene Glycol Impacts Conformation and Dynamics of Escherichia coli Prolyl-tRNA Synthetase Via Crowding and Confinement Effects. Biochemistry 2024; 63:1621-1635. [PMID: 38607680 PMCID: PMC11223479 DOI: 10.1021/acs.biochem.3c00719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/22/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024]
Abstract
Polyethylene glycol (PEG) is a flexible, nontoxic polymer commonly used in biological and medical research, and it is generally regarded as biologically inert. PEG molecules of variable sizes are also used as crowding agents to mimic intracellular environments. A recent study with PEG crowders revealed decreased catalytic activity of Escherichia coli prolyl-tRNA synthetase (Ec ProRS), where the smaller molecular weight PEGs had the maximum impact. The molecular mechanism of the crowding effects of PEGs is not clearly understood. PEG may impact protein conformation and dynamics, thus its function. In the present study, the effects of PEG molecules of various molecular weights and concentrations on the conformation and dynamics of Ec ProRS were investigated using a combined experimental and computational approach including intrinsic tryptophan fluorescence spectroscopy, atomic force microscopy, and atomistic molecular dynamic simulations. Results of the present study suggest that lower molecular weight PEGs in the dilute regime have modest effects on the conformational dynamics of Ec ProRS but impact the catalytic function primarily via the excluded volume effect; they form large clusters blocking the active site pocket. In contrast, the larger molecular weight PEGs in dilute to semidilute regimes have a significant impact on the protein's conformational dynamics; they wrap on the protein surface through noncovalent interactions. Thus, lower-molecular-weight PEG molecules impact protein dynamics and function via crowding effects, whereas larger PEGs induce confinement effects. These results have implications for the development of inhibitors for protein targets in a crowded cellular environment.
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Affiliation(s)
- Jessica Liebau
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Bethany F. Laatsch
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Joshua Rusnak
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Keegan Gunderson
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Brianna Finke
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Kassandra Bargender
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Alex Narkiewicz-Jodko
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Katelyn Weeks
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Murphi T. Williams
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Irina Shulgina
- Department
of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Karin Musier-Forsyth
- Department
of Chemistry and Biochemistry and Center for RNA Biology, The Ohio State University, Columbus, Ohio 43210, United States
| | - Sudeep Bhattacharyya
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
| | - Sanchita Hati
- Department
of Chemistry and Biochemistry, University
of Wisconsin-Eau Claire, Eau Claire, Wisconsin 54702, United States
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Xu G, Cheng K, Liu M, Li C. Studying protein stability in crowded environments by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2024; 140-141:42-48. [PMID: 38705635 DOI: 10.1016/j.pnmrs.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 05/07/2024]
Abstract
Most proteins perform their functions in crowded and complex cellular environments where weak interactions are ubiquitous between biomolecules. These complex environments can modulate the protein folding energy landscape and hence affect protein stability. NMR is a nondestructive and effective method to quantify the kinetics and equilibrium thermodynamic stability of proteins at an atomic level within crowded environments and living cells. Here, we review NMR methods that can be used to measure protein stability, as well as findings of studies on protein stability in crowded environments mimicked by polymer and protein crowders and in living cells. The important effects of chemical interactions on protein stability are highlighted and compared to spatial excluded volume effects.
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Affiliation(s)
- Guohua Xu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Kai Cheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, PR China.
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Majumdar S, Rastogi H, Chowdhury PK. Bridging Soft Interaction and Excluded Volume in Crowded Milieu through Subtle Protein Dynamics. J Phys Chem B 2024; 128:716-730. [PMID: 38226816 DOI: 10.1021/acs.jpcb.3c07266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The impact of macromolecular crowding on biological macromolecules has been elucidated through the excluded volume phenomenon and soft interactions. However, it has often been difficult to provide a clear demarcation between the two regions. Here, using temperature-dependent dynamics (local and global) of the multidomain protein human serum albumin (HSA) in the presence of commonly used synthetic crowders (Dextran 40, PEG 8, Ficoll 70, and Dextran 70), we have shown the presence of a transition that serves as a bridge between the soft and hard regimes. The bridging region is independent of the crowder identity and displays no apparent correlation with the critical overlap concentration of the polymeric crowding agents. Moreover, the dynamics of domains I and II and the protein gating motion respond differently, thereby bringing to the fore the asymmetry underlying the crowder influence on HSA. In addition, solvent-coupled and decoupled protein motions indicate the heterogeneity of the dynamic landscape in the crowded milieu. We also propose an intriguing correlation between protein stability and dynamics, with increased global stability being accompanied by eased local domain motion.
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Affiliation(s)
- Shubhangi Majumdar
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Harshita Rastogi
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
| | - Pramit K Chowdhury
- Department of Chemistry, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Irukuvajjula SS, Jithender Reddy G, Rao K, Vadrevu LR. Contrasting effect of ficoll on apo and holo forms of bacterial chemotaxis protein Y: Selective destabilization of the conformationally altered holo form. Int J Biol Macromol 2023; 232:123505. [PMID: 36736516 DOI: 10.1016/j.ijbiomac.2023.123505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/13/2023] [Accepted: 01/28/2023] [Indexed: 02/04/2023]
Abstract
Chemotaxis Y (CheY), upon metal binding, displays a drastic alteration in its structure and stability. This premise prompted us to study the effect of crowding on the two conformationally distinct states of the same test protein. A comparative analysis on the structure and thermal stability in the presence and absence of the macromolecular crowder, ficoll, and its monomeric unit, sucrose, revealed a contrasting effect of ficoll on the apo and holo forms. In the presence of ficoll while the thermal stability (Tm) of the apo form is enhanced, the thermal stability of the holo form is reduced. The selective lowering of Tm for the holo form in the combined presence of ficoll and sucrose and not in sucrose alone suggests that the contrasting effect is due to the macromolecular nature of ficoll. Since metal-protein interaction remains unperturbed in the presence of ficoll and Mg2+ sequestration is ruled out in a systematic manner the alternative possibility for the exclusive reduction in the thermal stability of the holo form is the ficoll-induced modulation of the relative population of apo and holo forms of CheY.
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Affiliation(s)
- Shivkumar Sharma Irukuvajjula
- Department of Biological Sciences, Birla Institute of Science and Technology - Pilani, Hyderabad Campus, Shamirpet, Hyderabad 500078, India.
| | - G Jithender Reddy
- NMR Division, Department of Analytical & Structural Chemistry, CSIR-Indian Institute of Chemical Technology, Ministry of Science and Technology, Uppal Road, Tarnaka, Hyderabad 500007, India
| | - Krishna Rao
- Tata Institute of Fundamental Research, 36/P, Gopanpally Mandal, Ranga Reddy District, Hyderabad, Telangana State 500107, India
| | - Late Ramakrishna Vadrevu
- Department of Biological Sciences, Birla Institute of Science and Technology - Pilani, Hyderabad Campus, Shamirpet, Hyderabad 500078, India
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